Past Questions

CHM 102 (ICH 102) Past Questions and Answers

Bystudentsdash November 8, 2024October 2, 2025

250 Generated Past Questions

The 1828 synthesis of urea by Wöhler is important because it demonstrated that:
A. Organic compounds can only be produced by living organisms
B. Organic compounds can be synthesized from inorganic substances
C. Proteins are identical to urea
D. Urea is an inorganic compound
Answer: B
Which element is central to organic chemistry?
A. Oxygen
B. Carbon
C. Nitrogen
D. Sulfur
Answer: B
Carbon can form four bonds because it has how many valence electrons?
A. 2
B. 4
C. 6
D. 8
Answer: B
A homologous series is defined by members that:
A. Share the same functional group and differ by CH₂ units
B. Have identical physical properties
C. Have the same molecular formula
D. Always contain a benzene ring
Answer: A
Which property is typical of organic compounds?
A. Always ionic
B. Low melting/boiling relative to inorganic salts (often) and covalent
C. High conductivity in solid state
D. Always crystalline
Answer: B
The IUPAC principle of selecting parent chain involves choosing the:
A. Longest continuous chain containing the principal functional group
B. Shortest chain available
C. Most branched chain
D. Chain containing the most hydrogen atoms
Answer: A
The suffix “-ol” in IUPAC nomenclature indicates a(n):
A. Aldehyde
B. Alcohol
C. Ketone
D. Amine
Answer: B
Structural isomers differ in:
A. Spatial arrangement only
B. Connectivity of atoms
C. Optical activity only
D. Molecular formula
Answer: B
Stereoisomers have:
A. Different connectivity of atoms
B. Same connectivity but different spatial arrangement
C. Different molecular formulas
D. Different elemental composition
Answer: B
A chiral carbon is one that:
A. Is sp hybridized
B. Has four different substituents and is tetrahedral
C. Is part of a double bond
D. Has two identical substituents
Answer: B
The general formula for alkanes is:
A. CnH2n
B. CnH2n+2
C. CnH2n-2
D. CnHn
Answer: B
An sp²-hybridized carbon typically has bond angles of about:
A. 180°
B. 120°
C. 109.5°
D. 90°
Answer: B
The uniqueness of carbon includes its ability to form:
A. Only ionic compounds
B. Long chains and rings (catenation) and multiple bond types
C. Only single bonds
D. Only aromatic compounds
Answer: B
Which test is used qualitatively to detect unsaturation (C=C)?
A. Tollens’ reagent
B. Bromine in CCl₄ decolorization
C. 2,4-DNP
D. Biuret reagent
Answer: B
Which class of compounds contains the carbonyl group (C=O) bonded to hydrogen?
A. Ketone
B. Aldehyde
C. Ether
D. Ester
Answer: B
A primary alcohol has the –OH group attached to a carbon bonded to:
A. Three other carbons
B. Two hydrogens and one carbon (one carbon)
C. No hydrogens
D. Only oxygen atoms
Answer: B
Heterolytic bond fission produces:
A. Two radicals
B. A cation and an anion
C. Two neutral atoms
D. Only photons
Answer: B
Homolytic bond fission produces:
A. Ions
B. Radicals (each atom keeps one electron)
C. Only protons
D. Carbocations only
Answer: B
The Kekulé structure of benzene incorrectly shows:
A. Delocalized π electrons around the ring
B. Alternating single and double bonds (localized)
C. Resonance — true depiction is resonance hybrid, not alternating fixed bonds
D. Aromatic stabilization
Answer: B
Which reagent is used for nitration of benzene?
A. Br₂/FeBr₃
B. HNO₃/H₂SO₄ (mixed acid)
C. NaOH only
D. H₂/Pd
Answer: B
In electrophilic aromatic substitution, electron-donating substituents generally direct:
A. Meta positions
B. Ortho and para positions
C. No substitution
D. Only para position if bulky
Answer: B
Which hybridization does carbon in ethyne (C≡C) exhibit?
A. sp³
B. sp²
C. sp
D. dsp²
Answer: C
Which compound is aromatic?
A. Cyclohexane
B. Benzene
C. Cyclobutene
D. 1,3,5-hexatriene
Answer: B
What is the IUPAC name for CH₃–CH₂–OH?
A. Methanol
B. Ethanol
C. Propanol
D. Ethene
Answer: B
Which of the following is a functional group?
A. Alkane chain
B. Hydroxyl (-OH)
C. Homologous series
D. Isomer
Answer: B
Which technique is best for purifying a high-boiling organic liquid?
A. Simple distillation
B. Fractional distillation
C. Recrystallization
D. Filtration
Answer: B
The inductive effect is the transmission of charge through:
A. Resonance only
B. Sigma bonds due to electronegativity differences
C. Pi bonds only
D. Magnetic fields only
Answer: B
A racemic mixture contains:
A. Only R enantiomer
B. Only S enantiomer
C. Equal amounts of R and S enantiomers
D. Only meso compound
Answer: C
Which is the correct IUPAC name for CH₃–CH(CH₃)–CH₃?
A. 2-Butane
B. 2-Methylpropane
C. 2-Methylbutane
D. Isobutane (common name) — IUPAC: propane derivative = 2-methylpropane
Answer: D
Which property increases down an alkane homologous series?
A. Solubility in water
B. Boiling point
C. Acidity
D. Reactivity with water
Answer: B
The benzene ring is planar because:
A. All carbons are sp³ hybridized
B. Carbons are sp² hybridized allowing trigonal planar geometry and conjugation
C. It contains only single bonds
D. It is saturated
Answer: B
Which is basic among the following functional groups?
A. Carboxylic acid
B. Amine
C. Ester
D. Aldehyde
Answer: B
The IUPAC priority order assigns highest suffix priority to:
A. Alkyl groups
B. Functional groups with highest oxidation state (e.g., carboxylic acids)
C. Halogens
D. Alkenes always
Answer: B
Which statement best describes resonance?
A. Molecule oscillates between resonance structures physically
B. Actual molecule is a resonance hybrid (delocalization of electrons) lower in energy than individual contributors
C. Resonance structures are distinct isomers
D. Resonance only applies to sigma bonds
Answer: B
Which is a vicinal dihalide?
A. Two halogens on same carbon
B. Two halogens on adjacent carbons
C. Halogen and OH on adjacent carbons only
D. Halogen on remote carbons only
Answer: B
Which reagent converts an alcohol to an alkyl halide via substitution (often SN2 for primary)?
A. SOCl₂ (or PBr₃)
B. NaBH₄
C. PCC
D. H₂O
Answer: A
The title “historical survey of organic compounds” most likely covers:
A. Modern spectroscopy only
B. Key discoveries like Wöhler, structural theory, Kekulé’s benzene, etc.
C. Only plastics invention
D. Only current synthetic methods
Answer: B
Which of the following is a common qualitative test for aldehydes?
A. 2,4-DNP only
B. Tollens’ reagent (silver mirror)
C. Bromine test only
D. Lucas test only
Answer: B
The empirical formula provides:
A. Exact molecular structure
B. Simple whole-number ratio of elements in a compound
C. Number of stereocenters
D. Bond angles
Answer: B
Which is a correct general formula for alkenes?
A. CnH2n+2
B. CnH2n
C. CnH2n-2
D. CnHn
Answer: B
In radical chain halogenation, the propagation steps involve:
A. Radical generation only
B. Radical abstraction and radical formation to continue chain (e.g., Cl• + RH → HCl + R•)
C. Ion formation only
D. Concerted pericyclic steps only
Answer: B
The term “functional group” refers to:
A. Carbon backbone only
B. Specific atom groups responsible for characteristic chemical reactions
C. Solvent used in reaction
D. Only heteroatoms present
Answer: B
Which compound will give a positive 2,4-DNP test?
A. Alcohols
B. Aldehydes and ketones (carbonyl compounds)
C. Alkanes
D. Ethers
Answer: B
Which of the following is an example of a constitutional isomer pair?
A. Butane and isobutane (C₄H₁₀)
B. Enantiomers of lactic acid
C. Cis- and trans-2-butene
D. Same compound drawn differently
Answer: A
The IUPAC name for CH₃–CH₂–CH₂–CH₃ is:
A. Butane
B. Pentane
C. Propane
D. Ethane
Answer: A
Which technique is most useful for identifying functional groups by characteristic vibrational absorptions?
A. ¹H NMR
B. IR spectroscopy
C. Mass spectrometry
D. UV-Vis spectroscopy
Answer: B
In a nucleophilic substitution SN2, stereochemistry at the stereocenter is:
A. Retained always
B. Inverted (Walden inversion) due to backside attack
C. Racemized always
D. Unchanged if tertiary center
Answer: B
Oxidation of a primary alcohol with strong oxidant often yields:
A. Alkane
B. Aldehyde (mild) then carboxylic acid (strong conditions)
C. Ketone always
D. Ether only
Answer: B
Which of the following is NOT part of the IUPAC system?
A. Systematic naming of compounds
B. Prioritizing functional groups for suffixes/prefixes
C. Arbitrary common names only
D. Rules for locants and numbering
Answer: C
Which class contains the –COOR group?
A. Amide
B. Ester
C. Ether
D. Alcohol
Answer: B
The major product of acid-catalyzed dehydration of a secondary alcohol typically is:
A. Alkene (elimination — Zaitsev product favored)
B. Alcohol unchanged
C. Ether only
D. Ketone only
Answer: A
A meso compound is:
A. Always optically active
B. Achiral despite having stereocenters due to internal symmetry
C. An enantiomeric pair only
D. Always a racemate
Answer: B
Which property is expected to change gradually down a homologous series?
A. Reactivity toward all reagents
B. Boiling point and melting point (generally increase)
C. Functional group type
D. Molecular formula remains identical
Answer: B
The most stable carbocation is:
A. Primary carbocation
B. Secondary carbocation
C. Tertiary carbocation (stabilized by hyperconjugation)
D. Methyl carbocation
Answer: C
Which reagent is commonly used for catalytic hydrogenation of alkenes?
A. Pd/C with H₂
B. NaBH₄ only
C. KMnO₄ only
D. HNO₃ only
Answer: A
An ether has which general bonding motif?
A. R–OH
B. R–O–R’
C. R–CO–R’
D. R–NH₂
Answer: B
Which transition metal commonly exhibits variable oxidation states and forms colored compounds?
A. Iron (Fe)
B. Argon (Ar)
C. Sodium (Na)
D. Neon (Ne)
Answer: A
The Kolbe electrolysis is associated with which type of organic transformation?
A. Oxidative decarboxylation giving radical coupling products from carboxylates
B. Reduction of carbonyls only
C. Hydrogenation of alkenes only
D. Hydrolysis of esters only
Answer: A
Which technique measures molecular mass (molecular weight) of a compound?
A. IR spectroscopy
B. Mass spectrometry (MS)
C. TLC only
D. UV-Vis only
Answer: B
Which reagent is used to oxidize secondary alcohols to ketones?
A. NaBH₄
B. PCC or Jones or KMnO₄
C. HCl only
D. H₂ only
Answer: B
Which is a typical bond angle in tetrahedral geometry?
A. 120°
B. 109.5°
C. 180°
D. 90°
Answer: B
Which of the following describes hyperconjugation?
A. Delocalization of electrons via overlap of σ bonds with adjacent empty or partially filled p orbitals stabilizing carbocations
B. Resonance of lone pairs only
C. Ionic bonding stabilization only
D. Hydrogen bonding effect only
Answer: A
Which of the following is a halogenation reagent for aromatic rings?
A. Cl₂/FeCl₃ (Lewis acid catalyst)
B. Br₂/UV only (radical addition to alkanes)
C. NaCl alone
D. H₂O only
Answer: A
The presence of a nitro group (-NO₂) on benzene usually:
A. Activates ring and directs ortho/para
B. Deactivates ring and directs meta
C. Causes ring to be non-reactive for all substitutions
D. Always results in addition reactions only
Answer: B
Which process is used to separate components of a mixture based on relative solubility in two immiscible solvents?
A. Distillation
B. Liquid–liquid extraction (separatory funnel)
C. Recrystallization
D. Filtration
Answer: B
Which of these is a conjugated diene?
A. 1,3-Butadiene
B. 1,4-Butadiene (not conjugated across single bonds appropriately)
C. Cyclohexane
D. Propane
Answer: A
The chemical behavior of functional groups is largely determined by:
A. Carbon chain length only
B. Functional group identity (electronegative atoms, electron distribution)
C. Color of compound only
D. Crystal structure only
Answer: B
Which reagent will form a Grignard reagent from an alkyl bromide?
A. R–Br + Mg in dry ether → R–MgBr
B. R–Cl + H₂O only
C. R–Br + NaOH only
D. R–Br + O₂ only
Answer: A
Which bond is stronger: a C–C single bond or a C=C double bond?
A. Single bond stronger
B. Double bond stronger (σ + π)
C. Both equal
D. Depends only on temperature
Answer: B
Which test differentiates between primary/secondary alcohols and tertiary alcohols?
A. Lucas test (tertiary alcohols react rapidly to form alkyl chloride — turbidity)
B. Tollens’ test only
C. 2,4-DNP only
D. Bromine test only
Answer: A
Which of the following is an example of an sp³ carbon?
A. Carbon in methane
B. Carbon in ethene double bond
C. Carbon in ethyne triple bond
D. Carbon in benzene ring
Answer: A
Which reaction is an example of nucleophilic acyl substitution?
A. Ester + OH⁻ → carboxylate + alcohol (saponification)
B. Radical halogenation only
C. Electrophilic aromatic substitution only
D. Diels–Alder only
Answer: A
Which is the correct IUPAC name for CH₃–CH₂–Cl?
A. Chloroethane
B. Ethyl chloride (common name) — IUPAC: chloroethane
C. 1-Chloroethane (both acceptable, but simplest: chloroethane)
D. All above essentially same naming forms
Answer: A
In aromatic chemistry, deactivating groups typically:
A. Increase reactivity towards electrophiles
B. Decrease reactivity and often direct meta
C. Always direct ortho/para
D. Convert ring to alkane
Answer: B
Which technique uses a stationary solid phase and mobile solvent to separate components?
A. Thin-layer chromatography (TLC) or column chromatography
B. Distillation only
C. Filtration only
D. Recrystallization only
Answer: A
Which of the following is a polar aprotic solvent that favors SN2 reactions?
A. Water
B. DMSO or DMF
C. Methanol
D. Ethanol
Answer: B
The mechanism of SN1 involves which key intermediate?
A. Carbocation
B. Carbanion
C. Radical only
D. Concerted transition state only
Answer: A
Which of the following is an example of an electrophile?
A. OH⁻
B. H⁺ (proton)
C. CN⁻
D. NR₂⁻
Answer: B
Which of the following indicates the presence of an alcohol in IR spectrum?
A. Sharp peak ~1700 cm⁻¹
B. Broad peak ~3200–3600 cm⁻¹ (O–H stretch)
C. Peak at 2100 cm⁻¹ only
D. No peaks at all
Answer: B
Which compound has a functional group that is basic and often protonated in acidic conditions?
A. Amine (R–NH₂)
B. Carboxylic acid (R–COOH)
C. Ester (R–COOR)
D. Ketone (R–CO–R)
Answer: A
Which of the following best defines catenation?
A. Tendency of carbon to form chains and rings with itself
B. Formation of ionic solids only
C. Exclusive formation of double bonds only
D. None of the above
Answer: A
Which is true about alkynes?
A. They have C≡C triple bonds and general formula CnH2n-2
B. They are saturated hydrocarbons
C. They have formula CnH2n+2
D. They are aromatic compounds by default
Answer: A
Which reagent gives a positive Tollens’ test?
A. Ketones typically negative; aldehydes positive (reduce Tollens’ reagent to metallic silver)
B. Alkanes only
C. Ethers only
D. Alcohols only
Answer: A
Which of the following best describes resonance energy of benzene?
A. Negative (destabilizing) relative to localized structures
B. Stabilization due to delocalized π electrons making benzene lower in energy than hypothetical localized triene
C. No difference between resonance forms
D. Always increases reactivity drastically
Answer: B
Which relation between boiling point and molecular weight in homologous series is generally correct?
A. Boiling point decreases with molecular weight
B. Boiling point increases with molecular weight (larger dispersion forces)
C. Boiling point independent of molecular weight
D. Branching increases boiling point always
Answer: B
Which reagent is used to form an alkoxide from an alcohol?
A. Strong base such as NaH or Na metal (ROH + Na → RONa + 1/2 H₂)
B. Weak acid only
C. H₂O only
D. NaCl only
Answer: A
In naming branched alkanes, substituents are named and then:
A. The longest chain is selected and substituents are alphabetized when assigning locants (ignore prefixes like di-, tri- for alphabetizing)
B. Shortest chain is chosen always
C. Substituents are ignored for numbering
D. Locants always start from left in drawing only
Answer: A
Which of the following is true for conjugated systems?
A. Conjugation lowers overall stability always
B. Conjugation allows delocalization of π electrons, often stabilizing and shifting UV-Vis absorption to longer wavelengths
C. Conjugation only occurs in saturated compounds
D. Conjugation always makes molecules colorless
Answer: B
The formation of an enolate from a carbonyl compound requires:
A. Strong base to remove an α-hydrogen forming resonance-stabilized enolate anion
B. Radical initiator only
C. Nothing — enolates form spontaneously always
D. Only acid catalysts produce enolates always (acid gives enol, base gives enolate)
Answer: A
Which of the following compounds would be most soluble in water?
A. Hexane
B. Ethanol (hydrogen bonding with water)
C. Benzene
D. Octane
Answer: B
Which of the following statements about chirality is correct?
A. Molecules with an internal plane of symmetry are always chiral
B. Molecules that are non-superimposable on their mirror images are chiral
C. All molecules with stereocenters are optically active always (racemic mixtures can be optically inactive overall)
D. Chirality only depends on double bonds
Answer: B
Which reagent is commonly used for oxidation of aldehydes to carboxylic acids?
A. KMnO₄ or Jones reagent (CrO₃/H₂SO₄) — strong oxidants
B. NaBH₄ (reducing)
C. H₂/Pd (reducing)
D. LiAlH₄ (reducing)
Answer: A
Which of the following best describes a sigma (σ) bond?
A. Side-by-side overlap of p orbitals
B. End-to-end overlap along internuclear axis (s–s, s–p, p–p along axis)
C. No orbital overlap
D. Only in ionic compounds
Answer: B
Which of the following is an ambident nucleophile?
A. CN⁻ (can attack through C or N)
B. OH⁻ only (single donor atom)
C. Cl⁻ only
D. NH₃ only
Answer: A
Which reagent and condition favor E2 elimination?
A. Strong base (e.g., t-BuOK), good leaving group, anti-periplanar geometry — concerted elimination
B. Weak base, polar protic solvent only
C. Radical initiator only
D. Transition metal catalysis only
Answer: A
Which of these is a π bond characteristic?
A. Formed by end-to-end overlap of hybrids
B. Side-to-side overlap of unhybridized p orbitals above and below bonding axis
C. Present between s orbitals only
D. Present in single bonds only
Answer: B
Which of the following is an example of a nucleophilic addition to a carbonyl?
A. Addition of CN⁻ to aldehyde to form cyanohydrin
B. Radical halogenation only
C. Electrophilic aromatic substitution only
D. Esterification only
Answer: A
Which metal is commonly used in cross-coupling reactions (e.g., Suzuki, Heck)?
A. Palladium (Pd) catalysts are common
B. Sodium only
C. Potassium only
D. Calcium only
Answer: A
The primary bonding in organic molecules is mostly:
A. Ionic bonding between metals and nonmetals
B. Covalent bonding between nonmetal atoms (shared electrons)
C. Metallic bonding only
D. Ionic lattice only
Answer: B
Which of the following correctly orders carbon hybridizations by increasing s-character?
A. sp³ < sp² < sp (i.e., sp³ least s-character, sp most s-character)
B. sp > sp² > sp³
C. sp³ = sp² = sp
D. sp² < sp³ < sp
Answer: A
Which functional group will show a strong C=O stretch near 1700 cm⁻¹ in IR?
A. Alcohol
B. Ketone or aldehyde or carboxylic acid (carbonyl)
C. Alkane
D. Ether
Answer: B
Which of the following is NOT true about benzene?
A. It undergoes addition reactions readily like alkenes under mild conditions
B. It is aromatic and favors substitution to preserve aromaticity
C. It has delocalized π electrons giving extra stabilization
D. Huckel’s rule (4n+2 π electrons, n=1 gives 6 π electrons) applies
Answer: A
Which mechanism leads to racemization when a chiral center forms a planar carbocation intermediate?
A. SN2
B. SN1 (planar carbocation can be attacked from either side giving racemization)
C. E2 only
D. Radical substitution only
Answer: B
Which of the following is a method for preparing nanoparticles by top-down approach?
A. Ball milling (mechanical grinding to produce small particles)
B. Chemical vapor deposition only
C. Sol–gel only
D. Wet chemical reduction only
Answer: A
Which reagent converts a carboxylic acid to an acid chloride?
A. SOCl₂ (thionyl chloride) or PCl₅/PCl₃
B. NaBH₄ only
C. H₂O only
D. H₂/Pd only
Answer: A
Which statement best describes electrophilicity?
A. Nucleophiles are electron-poor species that seek electrons
B. Electrophiles are electron-poor species that accept electron pairs from nucleophiles
C. Electrophiles donate electrons to nucleophiles always
D. Electrophiles are always anions
Answer: B
Which of the following is an example of geometrical (cis–trans) isomerism?
A. 2-Butene (cis and trans isomers)
B. Butane (no double bond)
C. 1-Butyne (triple bond)
D. Propane (no double bond)
Answer: A
Which reagent is used to convert an aldehyde to an alcohol (reduction)?
A. NaBH₄ (milder, reduces aldehydes/ketones to alcohols)
B. PCC (oxidant)
C. KMnO₄ (oxidant)
D. HNO₃ (oxidant)
Answer: A
Which statement about isoelectronic species is correct?
A. They have the same number of electrons but different numbers of protons or atoms (e.g., N₂ and CO)
B. They have identical chemical behavior always
C. They always have identical sizes
D. Not used in organic chemistry
Answer: A
Which of the following is a strong nucleophile commonly used in SN2?
A. I⁻ in polar aprotic solvent (good nucleophile and polarizable)
B. H₂O only
C. CO₂ only
D. N₂ only
Answer: A
Which of these is a primary amide functional group?
A. R–CONH₂
B. R–COOR
C. R–OH
D. R–NH–R
Answer: A
Which of the following increases with greater conjugation?
A. UV-Vis λmax shifts to shorter wavelength (hypsochromic)
B. λmax shifts to longer wavelength (bathochromic) and often increased absorption intensity
C. IR absorption disappears entirely
D. NMR signals vanish
Answer: B
Which reagent will oxidize an alkene to diol under cold, dilute conditions?
A. KMnO₄ (cold, dilute) gives syn dihydroxylation to vicinal diol
B. Ozone under reductive workup only gives carbonyls, not diols typically
C. H₂/Pd reduces double bond to alkane
D. NaBH₄ only reduces carbonyls
Answer: A
Which property of nanoparticles is critical for catalytic behavior?
A. High surface area to volume ratio increases active sites
B. Low surface area always increases catalysis
C. Bulk properties identical to nanoparticle properties always
D. Only color matters, not surface chemistry
Answer: A
Which of the following reagents adds across a double bond in anti-Markovnikov fashion via radical pathway?
A. HBr with peroxides (ROOR) gives anti-Markovnikov addition of HBr
B. HBr without initiator gives Markovnikov addition
C. H₂/Pd always gives addition of H₂ (hydrogenation) not regioselective by Markovnikov concept
D. Br₂ gives vicinal dibromide (no Markovnikov concept)
Answer: A
Which of the following is a common method for structural characterization of organic compounds giving information about hydrogen environments?
A. ¹H NMR spectroscopy
B. IR spectroscopy only
C. Mass spectrometry only
D. UV-Vis only
Answer: A
Which step in electrophilic aromatic substitution restores aromaticity?
A. Formation of sigma complex only
B. Deprotonation of sigma complex (loss of H⁺) to regenerate aromatic system
C. Radical chain propagation only
D. Addition across double bond only
Answer: B
Which of the following best describes a ketone?
A. R–C(=O)–R’ (carbonyl bonded to two carbons)
B. R–COOH only
C. R–OH only
D. R–NH₂ only
Answer: A
Which of the following is NOT an attribute of carbon that contributes to organic diversity?
A. Ability to form stable single, double, triple bonds
B. Catenation (forms long chains)
C. Limited oxidation states only +1 and +2
D. Ability to hybridize (sp³, sp², sp)
Answer: C
Which reagent is used in Friedel–Crafts acylation?
A. An acid chloride with AlCl₃ (Lewis acid catalyst) to install acyl groups on aromatic ring
B. Br₂ only
C. H₂ only
D. NaOH only
Answer: A
Which of the following is a common leaving group in substitution reactions?
A. Cl⁻, Br⁻, I⁻, and tosylate (OTs) are good leaving groups
B. H⁻ is a good leaving group always
C. R– is an excellent leaving group always
D. OH⁻ is a good leaving group in neutral conditions always
Answer: A
Which of the following best describes allylic stabilization?
A. Radical or carbocation adjacent to a double bond is stabilized by resonance delocalization over π system
B. Only σ bonds provide allylic stabilization
C. Allylic systems are destabilized always
D. No resonance possible in allylic systems
Answer: A
Which of the following is true for nano-sized gold particles compared to bulk gold?
A. They can show distinct colors due to surface plasmon resonance depending on size and aggregation
B. They are exactly same color as bulk gold regardless of size
C. They have identical optical properties always
D. They never interact with light
Answer: A
Which reagent is commonly used to protect carbonyls as acetals?
A. Reaction with an alcohol (e.g., ethylene glycol) under acid catalysis forms acetal (protecting group)
B. NaBH₄ only (reducing)
C. KMnO₄ only (oxidizing)
D. H₂ only
Answer: A
Which is the IUPAC name for CH₃–CH₂–CH₂–Cl?
A. 1-Chloropropane (or chloropropane; correct: 1-chloropropane)
B. 2-Chloropropane only
C. 1-Chloroethane only
D. Propyl chloride only (common name)
Answer: A
Which of the following best describes a methyl shift?
A. A rearrangement where a methyl group migrates to stabilize a carbocation intermediate (common in SN1 rearrangements)
B. Hydride abstraction only
C. Radical termination only
D. No migrations occur in carbocations
Answer: A
Which of these techniques gives molecular formula information by isotopic pattern?
A. Mass spectrometry (MS) provides molecular ion peak and isotopic pattern information
B. IR gives molecular formula directly
C. NMR gives molecular formula directly always
D. TLC gives molecular formula
Answer: A
Which of the following is a consequence of branching in alkanes?
A. Branching raises boiling point compared to straight-chain isomers always
B. Branching lowers boiling point compared to straight-chain isomers due to decreased surface area and weaker dispersion forces
C. Branching always increases solubility in water dramatically
D. Branching makes molecules ionic
Answer: B
Which reagent performs oxidation of primary alcohol to aldehyde without further oxidation to acid (mild)?
A. PCC (pyridinium chlorochromate) in CH₂Cl₂ (mild conditions)
B. KMnO₄ (strong oxidant → acid)
C. H₂/Pd (reducing)
D. NaBH₄ (reducing)
Answer: A
Which of the following is a class of organic compound containing a nitrogen directly bonded to carbonyl (–CONH–)?
A. Ester
B. Amide
C. Ether
D. Alcohol
Answer: B
Which statement best describes the Born–Haber-like considerations for stability of organometallic complexes?
A. Ligand field stabilization, metal electronic configuration, and thermodynamics (enthalpy/entropy) influence complex stability
B. Only color determines complex stability
C. Stability solely depends on ligand mass
D. No thermodynamic factors matter
Answer: A
Which type of isomerism does glucose and fructose exemplify?
A. Stereoisomerism only
B. Functional group isomerism (both C₆H₁₂O₆ but differ in carbonyl location — glucose is an aldose, fructose a ketose)
C. Conformational isomerism only
D. No isomerism
Answer: B
Which of the following best describes an sp hybridized carbon’s geometry?
A. Tetrahedral
B. Trigonal planar
C. Linear (180°)
D. Bent
Answer: C
Which of the following is true about benzene’s Hückel rule?
A. Aromatic if 4n π electrons (n integer)
B. Aromatic if 4n + 2 π electrons (n integer) — benzene has 6 π electrons (n=1)
C. Aromatic only if 10 π electrons always
D. Rule not applicable to planar rings
Answer: B
Which reagent is used for allylic bromination selectively?
A. NBS (N-bromosuccinimide) in presence of light or peroxides for allylic bromination
B. Br₂ with FeBr₃ for electrophilic bromination of aromatics
C. HBr only for addition across double bonds
D. KMnO₄ only (oxidation)
Answer: A
Which of the following is a Lewis acid?
A. AlCl₃ (accepts electron pairs)
B. NH₃ (donates electron pairs)
C. OH⁻ (donates electrons)
D. Cl⁻ (anion always)
Answer: A
Which of the following best defines the term “isomer”?
A. Same connectivity, different molecular formula
B. Same molecular formula but different arrangement of atoms (structural or stereoisomers)
C. Different elements entirely
D. Always enantiomers only
Answer: B
In naming substituted benzene, the prefixes for positions are:
A. 1,2 = ortho; 1,3 = meta; 1,4 = para
B. Ortho = 1,1; meta = 2,2; para = 3,3
C. Always use numbers only never use ortho/meta/para
D. Positions don’t matter in naming aromatic compounds
Answer: A
Which of the following is an example of a pericyclic reaction?
A. Diels–Alder (concerted [4+2] cycloaddition)
B. SN1 substitution only
C. Radical halogenation only
D. Nucleophilic acyl substitution only
Answer: A
Which of the following is an example of a functional group interconversion that protects an alcohol?
A. Convert alcohol to silyl ether (e.g., TBS) to protect against certain reagents, then deprotect with TBAF
B. Convert alcohol to alkane directly always
C. Convert alcohol to amine directly always
D. No protecting groups exist for alcohols
Answer: A
Which of the following statements about Brunauer–Emmett–Teller (BET) surface area is true in the context of nanoparticles?
A. BET measures surface area via gas adsorption and is important for catalytic nanoparticles (higher surface area often enhances catalytic activity)
B. BET only measures pore volume of bulk salts only
C. BET irrelevant to nanomaterials always
D. BET measures color changes only
Answer: A
Which reaction converts an alkene to an alcohol under Markovnikov addition?
A. Acid-catalyzed hydration (H₂O/H⁺) or oxymercuration–demercuration (gives Markovnikov alcohol without rearrangement)
B. Hydroboration–oxidation (gives anti-Markovnikov)
C. Hydrogenation (gives alkane)
D. Bromination (gives dibromide)
Answer: A
Which of the following is a consequence of resonance stabilization in conjugated carbonyls?
A. Lower reactivity toward nucleophiles at carbonyl carbon always
B. Delocalization reduces electrophilicity of carbonyl carbon when conjugated (e.g., α,β-unsaturated carbonyls have conjugate addition pathways)
C. Always increases rate of nucleophilic acyl substitution
D. Resonance removes carbonyl stretch in IR entirely
Answer: B
Which reagent can convert an ester to a carboxylic acid?
A. Hydrolysis under acidic or basic conditions (saponification under base gives carboxylate salt which after acidification gives carboxylic acid)
B. NaBH₄ only
C. H₂ only
D. Br₂ only
Answer: A
Which of the following is an important factor determining color of transition metal complexes?
A. Ligand field splitting (Δ) and nature of ligands influence wavelengths absorbed for d–d transitions
B. Only molecular weight determines color
C. Only presence of carbon atoms determines color
D. Color is independent of electronic transitions
Answer: A
Which of the following is true about SN2 reactions?
A. First order kinetics only
B. Bimolecular concerted mechanism where rate depends on concentration of both substrate and nucleophile
C. Proceeds via carbocation intermediate
D. Favored by tertiary centers
Answer: B
Which of the following is characteristic of primary carbons?
A. Carbon bonded to three other carbons
B. Carbon bonded to two hydrogen atoms and one carbon (R–CH₂–)
C. Has no hydrogen atoms attached
D. Always part of carbonyl
Answer: B
Which of the following reactions is an example of electrophilic addition?
A. HBr adding to propene to give bromoalkane (electrophile H⁺ attacks π bond)
B. SN2 substitution only
C. Radical polymerization only
D. Nucleophilic acyl substitution only
Answer: A
Which of the following best describes the role of ligands in coordination complexes?
A. They donate electron pairs to the metal center and influence geometry, reactivity, and electronic properties
B. They never interact with the metal
C. Ligands always are anionic only
D. Ligands only supply heat to the complex
Answer: A
Which of these is an example of a primary amine?
A. R–NH₂ (one carbon attached to nitrogen and two hydrogens)
B. R₂NH (secondary)
C. R₃N (tertiary)
D. R–CO–NH–R (amide)
Answer: A
Which reagent is commonly used for oxidation of alcohols to carbonyls under mild conditions?
A. PCC (primary alcohol → aldehyde; secondary → ketone without over-oxidation often)
B. NaBH₄ (reducing)
C. H₂/Pd (reducing)
D. O₂ only
Answer: A
Which of the following is true about boiling points of isomers?
A. More branched isomer has higher boiling point than straight-chain isomer always
B. Straight-chain isomer usually has higher boiling point than a more highly branched isomer due to greater surface area and dispersion forces
C. Branching has no effect on boiling point
D. Boiling point solely depends on color
Answer: B
Which reagent is used to remove silyl protecting groups (TBS/TBDMS)?
A. TBAF (tetrabutylammonium fluoride) in THF commonly used to deprotect silyl ethers
B. NaBH₄ only
C. H₂ only
D. Br₂ only
Answer: A
Which of the following statements about aromatic electrophilic substitution directing effects is correct?
A. Electron-donating groups (e.g., –OH, –OR, –NH₂) generally activate ring and direct ortho/para
B. Electron-withdrawing groups always activate and direct ortho/para
C. Nitro group activates ring and directs ortho/para
D. All substituents direct meta always
Answer: A
Which of the following is a factor in designing nanoparticle-based drug delivery systems?
A. Surface functionalization for targeting, size for biodistribution, biocompatibility, and release kinetics
B. Only color matters for delivery
C. Only density matters for delivery
D. Nanoparticles cannot be used for drug delivery
Answer: A
Which reagent is used for ozonolysis of alkenes with oxidative workup?
A. O₃ followed by H₂O₂ (oxidative workup) gives carboxylic acids or ketones depending on substitution
B. O₃ with reductive workup always gives alcohols only
C. O₃ never cleaves double bonds
D. O₃ with H₂ only gives alkanes only
Answer: A
Which of the following best describes an electrophile in organic reactions?
A. Electron-rich species seeking other electron-rich species
B. Electron-poor species accepting electron pair from nucleophile (e.g., carbocations, polarized carbonyls)
C. Always radicals only
D. Always anions only
Answer: B
Which of the following is a useful method to determine particle size distribution of colloidal nanoparticles?
A. Dynamic light scattering (DLS) provides hydrodynamic diameter distribution
B. TLC only
C. IR only
D. Mass spectrometry directly gives size distribution for nanoparticles in solution always
Answer: A
Which of the following is a characteristic test for phenols (distinguish from alcohols)?
A. Ferric chloride test (phenols give colored complex)
B. Tollens’ reagent
C. Br₂ test for alkenes only
D. 2,4-DNP only
Answer: A
Which of the following is true about meso compounds?
A. They are chiral and optically active
B. They contain stereocenters but are achiral due to internal plane of symmetry and are optically inactive
C. They always have no stereocenters
D. They are racemic mixtures only
Answer: B
Which of the following best describes catalytic converters’ function in cars?
A. Use transition metal catalysts (Pt, Pd, Rh) to catalyze redox reactions that convert CO, NOx, hydrocarbons into less harmful gases
B. Use salts to absorb CO only
C. Use nanoparticles to always increase toxicity
D. Use copper solely to catalyze hydrogenation of benzene
Answer: A
Which of the following is a correct representation of an ester hydrolysis (acidic)?
A. Ester + H₂O → carboxylic acid + alcohol (acid-catalyzed hydrolysis)
B. Ester + H₂ → alkane only
C. Ester + base → nothing happens
D. Ester always polymerizes only
Answer: A
Which of the following has the largest s-character: sp, sp², or sp³?
A. sp³
B. sp²
C. sp
D. All equal
Answer: C
Which of the following is NOT a typical signature of aromaticity?
A. Planar cyclic conjugated π system
B. 4n + 2 π electrons (Hückel rule)
C. Enhanced stability relative to acyclic analogues
D. Rapid addition reactions that break aromaticity under mild conditions
Answer: D
Which of the following describes the difference between homolytic and heterolytic bond cleavage?
A. Homolytic: each atom retains one electron → radicals; Heterolytic: pair of electrons goes to one atom → ions
B. Both produce ions only
C. Both produce radicals only
D. No difference at all
Answer: A
Which of the following is an aromatic heterocycle containing nitrogen?
A. Pyridine (aromatic with N contributing one lone pair outside π system)
B. Cyclohexane only
C. Cyclobutene only
D. Ethene only
Answer: A
Which reagent is typically used to carry out Friedel–Crafts alkylation?
A. Alkyl chloride with AlCl₃ (Lewis acid) as catalyst to form carbocation electrophile
B. H₂O only
C. NaOH only
D. KMnO₄ only
Answer: A
Which of the following best describes the role of sigma and pi bonds in double bonds?
A. Double bond consists of one σ and one π bond (σ from end-to-end overlap, π from side-by-side p orbital overlap)
B. Double bond is two σ bonds only
C. Double bond is two π bonds only
D. Double bond is ionic bond only
Answer: A
Which reagent will convert a nitrile to an amine?
A. Reduction with LiAlH₄ or catalytic hydrogenation (H₂/Pd) converts nitrile to primary amine (R–CH₂–NH₂)
B. Oxidation with KMnO₄
C. Ozonolysis only
D. Br₂ only
Answer: A
Which of the following is a physical method of purification for solids?
A. Recrystallization (dissolve in hot solvent, cool to precipitate pure crystals)
B. Bromination only
C. Oxidation only
D. Esterification only
Answer: A
Which of the following best describes Markovnikov’s rule?
A. In addition of HX to an unsymmetrical alkene, H attaches to carbon with fewer alkyl substituents, and X attaches to the more substituted carbon (stabilized carbocation)
B. H attaches to more substituted carbon always
C. X attaches to carbon with fewer substituents always
D. Rule only applies to aromatic compounds
Answer: A
Which reagent is commonly used for deprotonation of weakly acidic hydrogens (to form enolates)?
A. Strong bases like LDA (lithium diisopropylamide) or NaH
B. Water only
C. Ethanol only
D. HCl only
Answer: A
Which of the following best explains the cause of unique optical properties of metal nanoparticles (e.g., gold, silver)?
A. Surface plasmon resonance — collective oscillation of conduction electrons interacting with light, size- and environment-dependent
B. Nuclear decay only
C. Ionic bonding only
D. Color solely due to impurities, not size
Answer: A
Which of the following functional groups is most acidic?
A. Alkane C–H
B. Alcohol O–H
C. Carboxylic acid O–H
D. Ether O–R
Answer: C
Which of the following mechanisms is concerted (single-step) and stereospecific?
A. Diels–Alder cycloaddition (pericyclic reaction)
B. SN1 substitution (stepwise)
C. Free radical chain propagation (stepwise)
D. E1 elimination (stepwise)
Answer: A
Which of the following statements about carbene species is correct?
A. Carbenes are neutral species with divalent carbon having two nonbonded electrons and can exist as singlet or triplet depending on electron pairing
B. Carbenes are always positively charged
C. Carbenes are always aromatic
D. Carbenes are entirely stable with no reactivity
Answer: A
Which reagent is typically used for ozonolysis reductive workup to give aldehydes/ketones?
A. O₃ followed by (CH₃)₂S (dimethyl sulfide) or Zn/AcOH reduces ozonide to carbonyls (aldehydes/ketones)
B. O₃ with H₂O₂ always gives acids only
C. O₃ never used for double bond cleavage
D. O₃ with NaBH₄ only gives alcohols directly
Answer: A
Which of the following best describes an anomer in carbohydrate chemistry?
A. Stereoisomers that differ at the anomeric carbon (alpha vs beta) in cyclic sugars
B. Structural isomers only
C. Conformational isomers only
D. Not related to carbohydrates
Answer: A
Which of the following is an example of a chelating ligand?
A. Ethylenediamine (en) — bidentate ligand that binds through two nitrogen donors forming chelate ring(s)
B. Cl⁻ only (monodentate)
C. H₂O only (monodentate)
D. CO only (monodentate)
Answer: A
Which of the following reagents yields vicinal diol from alkene via syn addition?
A. Osmium tetroxide (OsO₄) followed by oxidative workup gives syn dihydroxylation (vicinal diol)
B. NBS only gives bromohydrin formation under other conditions
C. O₃ only gives cleavage, not diol directly
D. H₂/Pd gives hydrogenation not diol
Answer: A
Which of the following describes the general property of organic compounds regarding conductivity?
A. Most neutral organic compounds are poor conductors of electricity in solid state (nonionic covalent)
B. All organic compounds conduct electricity like metals
C. Organic compounds always conduct when dry
D. Conductivity always increases with molecular weight
Answer: A
Which of the following is TRUE about aldehydes and ketones in NMR?
A. Aldehyde protons typically appear downfield (~9–10 ppm) in ¹H NMR; carbonyl carbons appear around 190–220 ppm in ¹³C NMR
B. Aldehyde protons appear at 0–1 ppm always
C. Carbonyl carbons never show up in ¹³C NMR
D. Aldehydes and ketones look identical in all spectroscopies always
Answer: A
Which of the following is an organometallic reagent used to form carbon–carbon bonds?
A. Grignard reagent (R–MgX) reacts with electrophiles (carbonyls) to form new C–C bonds after workup
B. NaCl only
C. H₂O only
D. CO₂ only
Answer: A
Which of the following best describes the effect of electron-withdrawing groups on acidity of nearby hydrogens?
A. Electron-withdrawing groups (e.g., –NO₂) stabilize conjugate base via induction and increase acidity of adjacent hydrogens
B. Electron-withdrawing groups decrease acidity always
C. Electron-donating groups increase acidity always
D. No electronic effects on acidity
Answer: A
Which of the following is true for benzyl position reactivity?
A. Benzylic C–H bonds or benzylic radicals/cations are stabilized by resonance due to adjacency to aromatic ring, making benzylic positions reactive in substitution/oxidation
B. Benzylic position is inert always
C. Benzylic radicals are unstable always
D. Benzylic cations have no resonance stabilization
Answer: A
Which of the following reagents can perform oxidative cleavage of vicinal diols?
A. Periodic acid (HIO₄) or lead tetraacetate cleaves vicinal diols to carbonyl fragments
B. NaBH₄ only reduces diols to alkanes
C. H₂/Pd always reduces diols to cyclohexanes
D. O₂ only does nothing significant
Answer: A
Which of the following is an example of a protic solvent?
A. Water and alcohols (can donate protons and hydrogen bond)
B. DMSO (aprotic)
C. Acetone (aprotic but polar)
D. Hexane (nonpolar)
Answer: A
Which of the following statements about p-orbital overlap in conjugated systems is TRUE?
A. p-orbitals overlap sideways to create delocalized π system across conjugated atoms leading to stability and distinctive reactivity/spectra
B. p-orbitals do not overlap at all in conjugation
C. Conjugation eliminates all sigma bonds
D. Conjugation only occurs in saturated compounds
Answer: A
Which of the following is a typical oxidizing agent for converting alkene to epoxide under peracid conditions?
A. mCPBA (meta-chloroperbenzoic acid) epoxidizes alkenes to give epoxides (oxiranes) via concerted mechanism
B. NaBH₄ only reduces carbonyls not epoxidation
C. H₂/Pd reduces double bonds not epoxidation
D. KMnO₄ is oxidative but gives diol not epoxide under most conditions
Answer: A
Which of the following is correct for naming aliphatic compounds containing double bonds?
A. Number the longest chain containing the double bond with lowest possible locant to the double bond, suffix “-ene” and indicate position (e.g., but-2-ene)
B. Always number from right to left ignoring double bond position
C. Double bonds get no priority in numbering over substituents
D. Use prefix “di-ene” for single double bond only
Answer: A
Which of the following reagents is commonly used to reduce nitro groups to amines?
A. Catalytic hydrogenation (H₂/Pd) or chemical reduction with Fe/HCl or Sn/HCl converts Ar–NO₂ → Ar–NH₂
B. NaBH₄ only reduces carbonyls, not nitro reliably under mild conditions
C. KMnO₄ oxidizes nitro groups further
D. Br₂ only halogenates aromatics
Answer: A
Which of the following best describes the IUPAC rule for alphabetizing substituent names?
A. Alphabetize substituent names disregarding prefixes like di-, tri-, sec-, tert- (but keep iso as spelled for alphabetizing? convention: ignore multiplier prefixes (di-, tri-, tetra-) but not prefixes integral to name like iso-)
B. Count prefixes like di-, tri- for alphabetizing always
C. Do not alphabetize substituents
D. Always use common names regardless of alphabetizing
Answer: A
Which of the following is the typical product of ozonolysis (reductive workup) of cyclohexene?
A. A dialdehyde or diketone depending on symmetry (cleaves C=C to carbonyl fragments — for cyclohexene → adipaldehyde if ring opens under oxidative? but typical reductive ozonolysis of cyclohexene gives dialdehyde fragment(s))
B. Alkane always
C. Alcohols always only
D. No reaction
Answer: A
Which of the following is true about anti-Markovnikov hydration of alkenes using hydroboration–oxidation?
A. Hydroboration (BH₃/THF) followed by H₂O₂/NaOH yields alcohol where OH attaches to less substituted carbon (anti-Markovnikov) with syn stereochemistry
B. It yields Markovnikov alcohol exclusively
C. It gives ketone directly always
D. It yields vicinal dihalide instead
Answer: A
Which of the following best describes an sp² carbon’s geometry in a carbonyl group?
A. Tetrahedral
B. Trigonal planar around carbonyl carbon (approximately 120°) due to sp² hybridization
C. Linear (180°)
D. Pyramidal only
Answer: B
Which of the following is a reagent for converting alcohols into alkenes (dehydration)?
A. Concentrated H₂SO₄ or H₃PO₄ with heat to effect acid-catalyzed dehydration (E1/E2 pathways)
B. NaBH₄ only
C. H₂/Pd only
D. Ozone only
Answer: A
Which of the following statements is correct about amides?
A. Amides have resonance between the lone pair on nitrogen and carbonyl, making them less reactive than acid chlorides/esters toward nucleophilic acyl substitution
B. Amides are more reactive than acid chlorides always
C. Amides are ionic compounds only
D. Amides cannot be hydrolyzed under any conditions
Answer: A
Which of the following is characteristic of nanoparticle toxicity assessment?
A. Assessment must consider size, shape, surface chemistry, dose, exposure route, and biological responses — nanosafety is complex and case-specific
B. All nanoparticles are non-toxic always
C. Toxicity independent of surface chemistry always
D. Only chemical composition matters, not size
Answer: A
Which of these is a typical product of acid-catalyzed esterification (Fischer esterification)?
A. Carboxylic acid + alcohol → ester + water (acid-catalyzed equilibrium)
B. Ester → amide only always
C. Alcohol → alkane only
D. Ester → ketone only
Answer: A
Which of the following describes hypervalency or expanded octet?
A. Observed for elements in periods 3 and higher (e.g., P, S) where more than eight electrons can be accommodated due to d-orbitals or resonance structures — carbon does not expand octet commonly
B. Carbon commonly expands its octet to 10 electrons in stable compounds
C. Only hydrogen expands octet frequently
D. Expanded octet irrelevant to main group chemistry
Answer: A
Which of the following reagents is used for the Sandmeyer reaction to replace diazonium group with halide?
A. CuCl or CuBr with diazonium salt to introduce Cl or Br (Sandmeyer)
B. NaBH₄ only
C. H₂ only
D. KMnO₄ only
Answer: A
Which of the following is an example of a heterolytic cleavage product pair?
A. H–Cl → H⁺ + Cl⁻ (heterolytic)
B. Cl–Cl → Cl• + Cl• (homolytic)
C. C–C → C• + C• (homolytic)
D. None of the above
Answer: A
Which of the following spectroscopic techniques is most useful for identifying functional groups such as OH, C=O, NH?
A. IR spectroscopy (vibrational frequencies give diagnostic bands)
B. NMR only gives environment for H/C but not directly vibrational signatures
C. Mass spectrometry only gives mass fragments
D. TLC only separates but not identify functional groups specifically
Answer: A
Which of the following is an example of chain-growth polymerization initiated by radicals?
A. Radical polymerization of ethylene derivatives where initiation produces radical, propagation adds monomers, termination stops chain
B. Step-growth condensation polymerization only
C. Ionic polymerization only
D. Electrochemical polymerization only
Answer: A
Which of the following best describes the principle of Green Chemistry relevant to organic synthesis?
A. Designing processes to reduce waste, use safer reagents, maximize atom economy, and minimize environmental impact
B. Use of any reagent regardless of toxicity always
C. Always perform reactions at very high temperatures to save time regardless of energy consumption
D. Maximize hazardous by-products only
Answer: A
Which of the following reagents effects oxidative cleavage of alkenes to carboxylic acids/ketones under strong conditions?
A. Hot, concentrated KMnO₄ oxidizes alkenes to carbonyl-containing products (ketones, carboxylic acids) depending on substitution
B. H₂/Pd reduces double bonds instead
C. NaBH₄ reduces carbonyls not cleave alkenes
D. Br₂ only halogenates not oxidatively cleave to carbonyls under typical conditions
Answer: A
Which of the following is true about the inductive (-I) and mesomeric (-M/+M) effects?
A. Inductive transmitted via sigma bonds due to electronegativity; mesomeric (resonance) transmitted via π system; both influence reactivity and acidity/basicity
B. Inductive transmitted via pi bonds only always
C. Mesomeric effect is only magnetic in nature
D. Both effects are identical and indistinguishable
Answer: A
Which of the following is the expected product when benzene reacts with Cl₂ in presence of FeCl₃?
A. Chlorobenzene via electrophilic aromatic substitution (EAS)
B. 1,2-dichloroethane via addition across an alkene (not relevant for benzene under EAS conditions)
C. Benzene chloride addition product permanently (destroys aromaticity) — not favored under EAS conditions
D. No reaction
Answer: A
Which of the following is a good method for monitoring the progress of an organic reaction qualitatively and quickly?
A. Thin-layer chromatography (TLC) to see disappearance/appearance of spots and Rf changes
B. Boiling point measurement only (slow)
C. Mass spectrometry only (requires sample prep and instrumentation)
D. Visual color only (not reliable)
Answer: A
Which of the following reagents converts an alcohol into a tosylate (good leaving group) while retaining configuration?
A. p-TsCl (p-toluenesulfonyl chloride) with pyridine converts ROH → ROTs, good leaving group for subsequent substitution/elimination without initial inversion
B. NaBH₄ only reduces carbonyls
C. H₂ only reduces unsaturated bonds
D. Br₂ only halogenates otherwise
Answer: A
Which of the following is true about benzene nitration mechanism?
A. Mixed acid (HNO₃/H₂SO₄) generates NO₂⁺ electrophile; benzene attacks electrophile to give sigma complex followed by deprotonation to restore aromaticity
B. Nitration proceeds via radical chain only always
C. Nitration directly substitutes via SN2 on benzene ring (not possible)
D. Nitration adds NO₂ across double bonds destroying aromaticity permanently always
Answer: A
Which of the following is most acidic among these hydrogens?
A. Alkane C–H ~50 pKa (very weakly acidic)
B. α-Hydrogen of carbonyl compounds (pKa ~20) more acidic due to resonance stabilization of enolate
C. Alcohol O–H pKa ~16–18 (moderate)
D. Carboxylic acid O–H pKa ~4–5 (most acidic among listed in ordinary organic molecules)
Answer: D
Which of the following is an example of an electrophilic addition that gives vicinal dihalide?
A. Addition of Br₂ to alkene (Br₂ adds across double bond anti to give vicinal dibromide)
B. Hydrogenation gives alkanes not dihalides
C. Hydroboration gives alcohols after oxidation not dihalides
D. Ozonolysis gives carbonyls not dihalides
Answer: A
Which of the following best describes an enantiomer?
A. Non-superimposable mirror image of a chiral molecule with identical physical properties in achiral environment except direction of optical rotation
B. A constitutional isomer only
C. A meso compound always
D. Identical mirror images (superimposable)
Answer: A
Which of the following is the major product of acid-catalyzed hydration of 2-methylpropene?
A. 2-Methyl-2-propanol (tert-butanol) via Markovnikov addition to give tertiary alcohol
B. 1-Butanol always
C. 2-Methyl-1-propanol only
D. No reaction occurs
Answer: A
Which property is generally exploited to separate organic compounds by column chromatography?
A. Differences in polarity and affinity for stationary phase (silica gel) and mobile phase allowing separation based on Rf values
B. Only density differences matter in column chromatography
C. Column chromatography only used for inorganic salts separation
D. Column chromatography never used for organic mixtures
Answer: A
Which of the following reagents is used to convert a primary amine to a diazonium salt (on aromatic amine)?
A. NaNO₂ and HCl at 0–5°C converts Ar–NH₂ → Ar–N₂⁺ (diazonium) which can be used in Sandmeyer and other substitution reactions
B. NaBH₄ only
C. H₂/Pd only
D. KMnO₄ only
Answer: A
Which of the following is true about the benzyl radical stability?
A. Benzylic radicals are resonance-stabilized due to delocalization into the aromatic ring and thus more stable than typical alkyl radicals
B. Benzylic radicals are extremely unstable always
C. Benzylic radicals cannot form under any condition
D. Benzylic radicals are identical in stability to methyl radicals always
Answer: A
Which of the following best describes the principle of mass defect and high-resolution mass spectrometry?
A. High-resolution MS distinguishes molecular formulas by small differences in exact mass due to isotopic masses and mass defect allowing elemental composition determination
B. Mass spectrometry cannot determine elemental composition
C. High-resolution MS only gives color information
D. Mass spec only identifies functional groups, not mass
Answer: A
Which of the following is used to prepare nitriles from primary amides via dehydration?
A. P₂O₅ or SOCl₂ or other dehydrating agents convert R–CONH₂ → R–CN (nitrile) under dehydration conditions
B. NaBH₄ only reduces amides not dehydrate
C. H₂ only reduces/ hydrogenates not dehydrate
D. KMnO₄ only oxidizes not dehydrate
Answer: A
Which of the following best describes a “benzylic oxidation”?
A. Oxidation of benzylic C–H (adjacent to aromatic ring) using KMnO₄ or other oxidants to carboxylic acid if benzylic hydrogen(s) present (alkyl → carboxylic acid)
B. Oxidation of aromatic ring itself to break aromaticity always
C. Cannot oxidize benzylic positions
D. Benzylic oxidation gives alkanes always
Answer: A
Which of the following is a typical reagent for dehydration of alcohol under E2 conditions to form alkenes with strong base?
A. t-BuOK in tert-butanol (strong, sterically hindered base favoring E2)
B. NaBH₄ only reduces not eliminate
C. H₂/Pd reduces double bonds not eliminate alcohols
D. KMnO₄ only oxidizes not dehydrate
Answer: A
Which of the following is true about meso compounds in context of stereochemistry?
A. Meso compounds contain stereocenters but are achiral due to internal symmetry and show no optical activity
B. Meso compounds are always chiral and rotate plane-polarized light strongly
C. Meso compounds never contain stereocenters
D. Meso compounds are always racemic mixtures of two enantiomers
Answer: A
Which of the following is true about oxidative addition and reductive elimination in organometallic catalysis?
A. Oxidative addition increases metal oxidation state and coordination number; reductive elimination is reverse, important in cross-coupling cycles (e.g., Pd-catalyzed)
B. Oxidative addition decreases metal oxidation state always
C. Reductive elimination increases metal oxidation state always
D. These concepts are irrelevant in organometallic catalysis
Answer: A
Which of the following is a common method to synthesize primary amines from nitriles?
A. Hydrogenation (H₂ with catalyst) or LiAlH₄ reduction of nitrile gives primary amine R–CH₂–NH₂
B. Oxidation with KMnO₄ only gives acids not amines
C. Ozonolysis only cleaves double bonds not reduce nitriles
D. Nitriles cannot be converted to amines
Answer: A
Which of the following best explains the relationship between melting point and symmetry?
A. More symmetrical molecules pack better in crystal lattice and often have higher melting points than less symmetrical isomers
B. Symmetry always lowers melting point
C. Symmetry has no effect on melting point
D. Symmetry only affects color not melting point
Answer: A
Which of the following reagents is used for the conversion of an alcohol to an aldehyde by mild oxidation (primary alcohol → aldehyde)?
A. PCC in dichloromethane (mild, stops at aldehyde)
B. KMnO₄ (strong, overoxidizes to acid)
C. H₂/Pd (reduces, not oxidizes)
D. NaBH₄ (reducing)
Answer: A
Which of the following statements best describes a “sigma complex” (arenium ion) in EAS?
A. Sigma complex is non-aromatic intermediate formed when aromatic ring bonds to electrophile; positive charge is delocalized over ring then deprotonation regenerates aromaticity
B. Sigma complex is radical cation always
C. Sigma complex is stable permanent product
D. Sigma complex is never formed in EAS
Answer: A
Which of the following is a method to functionalize carbon nanotubes for dispersion in aqueous media?
A. Covalent functionalization (e.g., oxidation to introduce –COOH groups) or noncovalent wrapping (surfactants, polymers) to improve solubility/stability
B. Only heating nanotubes to high temp changes solubility always
C. Nanotubes cannot be functionalized at all
D. Only mechanical grinding disperses without chemical modification forever
Answer: A
Which of the following best describes the stability trend of carbanions?
A. More substituted carbanions always more stable due to hyperconjugation (actually alkyl groups donate electron density and destabilize carbanions; resonance-stabilized carbanions are more stable) — correct principle: resonance > inductive effects; alkyl substitution destabilizes carbanions (opposite of carbocations)
B. Tertiary carbanion is most stable always
C. Carbanion stability unaffected by resonance or substituents
D. Carbanions are stabilized by electron-withdrawing groups and resonance; alkyl substituents destabilize due to electron-donating inductive effects
Answer: D
Which reagent is commonly used to convert carboxylic acid into methyl ester (Fischer esterification)?
A. Methanol with acid catalyst (H₂SO₄) converts R–COOH + MeOH ⇌ R–COOMe + H₂O (reversible)
B. NaBH₄ only reduces carbonyls not esterify carboxylic acids
C. H₂ only reduces unsaturated bonds not esterify
D. KMnO₄ only oxidizes not esterify
Answer: A
Which of the following best describes the mechanism of aromatic sulfonation?
A. Electrophilic aromatic substitution where SO₃ (or SO₃·H₂SO₄ complex) acts as electrophile forming sigma complex then deprotonation restores aromaticity
B. Radical substitution only
C. Free radical polymerization only
D. Sulfonation never occurs on aromatic rings
Answer: A
Which of the following best describes the use of an internal standard in quantitation (e.g., GC)?
A. Internal standard is a compound of known amount added to sample to correct for injection/sample loss and allow quantitation by response ratio relative to analyte
B. Internal standard is only used to change color of sample
C. Internal standard unnecessary for quantitation always
D. Internal standard always reacts with analyte to give new product
Answer: A
Which of the following is true about allylic carbocations?
A. Allylic carbocations are resonance stabilized by delocalization over the adjacent π system and thus more stable than simple primary carbocations
B. Allylic carbocations are least stable compared to primary carbocations always
C. They cannot form under any conditions
D. Allylic carbocations are only stabilized by hyperconjugation not resonance
Answer: A
Which of the following is true about substitution at sp² hybridized carbon (e.g., vinyl halide) by SN2?
A. SN2 at sp² carbon is generally unfavorable due to geometry and partial double bond character; vinylic halides do not undergo SN2 easily
B. SN2 at sp² carbon occurs readily always
C. Vinylic halides are excellent substrates for SN2
D. SN2 is the typical mechanism for aryl halides too
Answer: A
Which of the following is an example of a nonclassical carbocation stabilization motif?
A. Bridged and delocalized carbocations such as norbornyl cation where positive charge delocalizes over framework (nonclassical) — controversial historically but accepted in many cases
B. Carbocations have no delocalization possible ever
C. Only methyl cation is classical, others nonclassical always
D. Carbocations are never stabilized by neighboring bonds
Answer: A
Which of the following is a common analytical technique for studying surface morphology of nanoparticles?
A. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) provide morphological and size information
B. TLC only provides separation not morphology
C. IR only gives functional groups not morphology
D. Melting point measurement only gives morphology always
Answer: A
Which reagent is commonly used for the reduction of nitrobenzene to aniline?
A. Fe/HCl or Sn/HCl or catalytic hydrogenation (H₂/Pd) reduce Ar–NO₂ → Ar–NH₂
B. KMnO₄ only oxidizes not reduce nitro groups
C. NaBH₄ only reduces carbonyls not nitro under mild conditions usually
D. Ozone never reduces nitro groups
Answer: A
Which of the following is true regarding optical activity?
A. Only chiral molecules (non-superimposable on mirror image) rotate plane-polarized light; enantiomers rotate equal magnitude opposite directions; racemic mixtures show no net rotation
B. Achiral molecules rotate light strongly always
C. Racemic mixtures rotate light strongly in one direction always
D. Optical activity irrelevant to stereochemistry
Answer: A
Which reagent converts alkyl halide to alkene under E2 conditions using a bulky base to favor less substituted alkene (Hofmann)?
A. t-BuOK (sterically hindered base favors Hofmann elimination in some cases)
B. NaCl only
C. H₂O only
D. Pd/C only
Answer: A
Which of the following best describes the concept of atom economy in green chemistry?
A. Atom economy measures how much of the reactants’ atoms are incorporated into desired product — higher atom economy is greener/sustainable
B. Atom economy is irrelevant to green chemistry
C. Atom economy always low for all reactions and cannot be improved
D. Atom economy only applied to metals not organic molecules
Answer: A
Which of the following is an example of a good leaving group for SN1 and SN2 reactions?
A. Tosylate (OTs) — good leaving group when formed from alcohols; halides Cl⁻, Br⁻, I⁻ also good leaving groups
B. Hydride (H⁻) is a good leaving group always
C. Phenyl anion always leaves easily
D. R– (carbanion) leaves readily always
Answer: A
Which of the following statements about NMR coupling constants (J) is correct?
A. Vicinal ³J(H–H) coupling depends on dihedral angle (Karplus relationship) and typical values vary for cis vs trans vs gauche relationships
B. Coupling constants give boiling points directly
C. Coupling constants are always zero for all protons
D. Coupling constants only used in IR spectroscopy not NMR
Answer: A
Which of the following reagents will deprotect an acetal under acidic aqueous conditions?
A. Aqueous acid (H₃O⁺) hydrolyzes acetal back to carbonyl and alcohols (deprotection)
B. Strong base always deprotects acetal without acid
C. NaBH₄ deprotects acetal by reducing carbonyl only
D. Ozone only deprotects acetal always
Answer: A
Which of the following best describes the reactivity of aryl halides in SNAr reactions?
A. Nucleophilic aromatic substitution (SNAr) occurs on aryl halides activated by electron-withdrawing groups (e.g., –NO₂) ortho/para to the leaving group; mechanism via Meisenheimer complex (addition–elimination)
B. Aryl halides easily undergo SN2 at sp² carbon always
C. Aryl halides never undergo nucleophilic substitution under any conditions
D. SNAr always occurs without electron-withdrawing groups required
Answer: A
Which of the following is an example of a reaction showing regioselectivity?
A. Addition of HBr to propene giving 2-bromopropane (Markovnikov) as major product — regioselective outcome based on carbocation stability
B. Radical coupling only shows no regioselectivity
C. SN2 always gives two regioisomers equally
D. Radical halogenation gives single product only always
Answer: A
Which of the following statements about solvents is correct in terms of reaction mechanisms?
A. Polar protic solvents stabilize ions and favor SN1 by stabilizing carbocations and leaving groups; polar aprotic solvents favor SN2 by not solvating nucleophiles strongly
B. Solvent has no effect on reaction mechanism or rate
C. Polar aprotic solvents always favor SN1
D. Polar protic solvents always favor SN2 exclusively
Answer: A
Which of the following describes the main idea of Huckel’s rule for aromaticity?
A. Monocyclic, planar, conjugated systems with 4n+2 π electrons exhibit aromatic stability (n = 0,1,2,…)
B. Any cyclic conjugated molecule is aromatic regardless of electron count
C. Aromaticity unrelated to electron count or planarity
D. Huckel’s rule applies only to benzene derivatives not other rings
Answer: A
Which of the following is a useful oxidative cleavage reagent for alkenes that yields carboxylic acids/ketones depending on substitution?
A. Ozonolysis with oxidative workup (O₃ / H₂O₂) or hot KMnO₄ produce carbonyl or carboxyl products depending on substitution
B. H₂/Pd only reduces double bonds not cleave
C. NaBH₄ reduces carbonyls not cleave alkenes
D. Br₂ only adds across double bonds not cleave oxidative products
Answer: A
Which of the following best summarizes reasons carbon is central to organic chemistry?
A. Carbon’s tetravalency, catenation ability (form long chains and rings), multiple bond formation (single/double/triple), and range of hybridizations (sp³, sp², sp) provide huge structural diversity enabling life and synthetic complexity
B. Carbon only forms ionic salts and therefore not central to organic chemistry
C. Carbon is inert and does not form diverse compounds
D. Carbon cannot form multiple bonds so limited chemistry
Answer: A

200 Generated Past Questions for Practice

What is the simplest organic compound?
A. Ethane
B. Methane
C. Ethene
D. Benzene
Answer: B
Which element is the backbone of organic chemistry?
A. Oxygen
B. Nitrogen
C. Carbon
D. Hydrogen
Answer: C
In organic chemistry, a functional group is best defined as:
A. The entire molecule
B. A group of atoms responsible for characteristic reactions
C. Only aromatic rings
D. Only hydrogen atoms
Answer: B
Which hybridization corresponds to carbon in ethene (C=C)?
A. sp
B. sp²
C. sp³
D. dsp²
Answer: B
What type of bond is formed by overlapping of two sp³ orbitals?
A. π bond
B. σ bond
C. Ionic bond
D. dative bond
Answer: B
Homolytic bond fission produces:
A. Ions
B. Radicals
C. Protons
D. Electrophiles
Answer: B
Heterolytic bond fission gives:
A. Two radicals
B. A cation and an anion
C. Two electrons only
D. Two protons
Answer: B
Benzene is aromatic because it has:
A. 4 π electrons
B. 6 π electrons in a conjugated cyclic system (Hückel’s rule)
C. Only sigma bonds
D. Nonconjugated double bonds
Answer: B
Which is the molecular formula for ethyne (acetylene)?
A. C₂H₄
B. C₂H₂
C. C₃H₄
D. C₂H₆
Answer: B
An sp-hybridized carbon has what geometry?
A. Tetrahedral
B. Trigonal planar
C. Linear
D. Bent
Answer: C
Which hydrocarbon is saturated?
A. Ethene
B. Ethyne
C. Ethane
D. Benzene
Answer: C
Markovnikov’s rule predicts the regiochemistry of:
A. Radical substitutions only
B. Electrophilic addition to unsymmetrical alkenes
C. Nucleophilic substitution SN2 only
D. Aromatic substitution
Answer: B
Zaitsev’s rule predicts the major product of:
A. Electrophilic addition
B. Elimination reactions (more substituted alkene)
C. Nucleophilic addition
D. Radical halogenation
Answer: B
Which is an example of an alkane?
A. Ethene
B. Propane
C. Ethyne
D. Benzene
Answer: B
What is the IUPAC suffix for alcohols?
A. -one
B. -ol
C. -ene
D. -al
Answer: B
A primary alcohol has the OH group attached to:
A. A carbon bonded to three other carbons
B. A carbon bonded to two other carbons
C. A carbon bonded to one other carbon
D. A hydrogen only
Answer: C
Which reagent is commonly used to oxidize primary alcohols to aldehydes (mild)?
A. NaBH₄
B. PCC
C. H₂/Pd
D. LiAlH₄
Answer: B
An ether functional group contains:
A. -COOH
B. -O- between two carbons
C. -NH₂
D. -OH
Answer: B
Which is a characteristic test for alkenes?
A. Lucas test
B. Bromine in CCl₄ decolorization
C. Tollens’ reagent
D. 2,4-DNP
Answer: B
A tertiary carbon is bonded to how many other carbon atoms?
A. One
B. Two
C. Three
D. Zero
Answer: C
Which configuration is defined by non-superimposable mirror images?
A. Conformers
B. Enantiomers
C. Isotopes
D. Mesomers
Answer: B
Which type of bonding involves sharing of electron pairs?
A. Ionic bonding
B. Covalent bonding
C. Metallic bonding
D. Hydrogen bonding
Answer: B
The overlap of p orbitals creates which bond type?
A. σ bond only
B. π bond only
C. Both σ and π bonds depending on context
D. Ionic bond
Answer: B
Which hydrocarbon has the general formula CnH2n+2?
A. Alkenes
B. Alkynes
C. Alkanes
D. Aromatics
Answer: C
The IUPAC name for CH₃CH₂CH₂CH₃ is:
A. Butane
B. Propane
C. Ethane
D. Pentane
Answer: A
Which reaction type involves addition of HX to an alkene?
A. Elimination
B. Addition (electrophilic)
C. Substitution
D. Rearrangement
Answer: B
Which species is electron-rich and seeks electrophiles?
A. Nucleophile
B. Electrophile
C. Radical cation
D. Carbocation
Answer: A
In radical halogenation of methane, the initiation step produces:
A. Carbocations
B. Radicals (Cl• from Cl₂ homolysis)
C. Ions only
D. Alkenes
Answer: B
Which of these is an aromatic heterocycle?
A. Cyclohexane
B. Pyridine
C. Cyclopentadiene
D. Propene
Answer: B
Electrophilic aromatic substitution commonly proceeds via formation of:
A. Carbocation intermediate (arenium ion / sigma complex)
B. Radical anion
C. Free radical only
D. Pericyclic transition state only
Answer: A
Which substituent directs ortho/para in electrophilic aromatic substitution?
A. Nitro group (-NO₂)
B. Alkyl group (-CH₃)
C. Carbonyl (-C=O)
D. Sulfonyl (-SO₃H)
Answer: B
Nitrobenzene is deactivated and directs substitution to:
A. Ortho/para
B. Meta
C. Both equally
D. No substitution possible
Answer: B
Which bond fission is heterolytic in nature?
A. Cl–Cl → Cl• + Cl•
B. H–Cl → H⁻ + Cl⁺
C. H–Cl → H⁺ + Cl⁻
D. C–C → C• + C•
Answer: C
Which of the following describes a π bond?
A. Overlap of hybrid orbitals end-to-end
B. Side-by-side overlap of unhybridized p orbitals
C. Ionic interaction between ions
D. d-orbital overlap only
Answer: B
The bond angle around an sp³ carbon is approximately:
A. 180°
B. 120°
C. 109.5°
D. 90°
Answer: C
A grignard reagent contains:
A. R–Mg–X (organomagnesium halide)
B. R–Li only
C. R–H only
D. R–OH only
Answer: A
In SN2 reactions, the nucleophile attacks from:
A. Same side as leaving group
B. Opposite side (backside) causing inversion of configuration
C. Either side equally with no stereochemical consequence
D. Only planar molecules
Answer: B
An SN1 reaction rate depends on:
A. Concentration of nucleophile only
B. Concentration of substrate (first order)
C. Temperature only
D. Presence of light only
Answer: B
Which alkene is more substituted and usually more stable?
A. 1-Butene
B. 2-Butene (trans)
C. Ethene
D. 1-Pentene
Answer: B
Hydrogenation of an alkene yields:
A. An alkyne
B. An alkane
C. An alcohol directly under standard conditions
D. A ketone
Answer: B
Which catalyst commonly hydrogenates alkenes?
A. Pd/C or Pt or Ni
B. H₂O only
C. NaCl
D. KMnO₄
Answer: A
Which is a vicinal dihalide?
A. Two halogens on the same carbon
B. Two halogens on adjacent carbons
C. Halogen and hydroxyl on same carbon
D. Halogen on terminal carbon only
Answer: B
The IUPAC name for CH₃–CH=CH–CH₃ (trans) is:
A. But-2-ene
B. But-1-ene
C. 2-Butyne
D. Butane
Answer: A
Which is a characteristic of transition elements?
A. Only s-block elements
B. Variable oxidation states and formation of colored compounds
C. No d electrons
D. Only form ionic bonds
Answer: B
Ligands that donate two pairs of electrons to a metal center are called:
A. Monodentate
B. Bidentate
C. Anionic only
D. None of the above
Answer: B
A chelate is formed when:
A. A monodentate ligand binds once
B. A polydentate ligand binds creating a ring with the metal
C. A ligand dissociates
D. Metal oxidizes only
Answer: B
Which of the following is an example of nucleophilic addition?
A. Addition of HBr to alkene
B. Addition of CN⁻ to a carbonyl (forming cyanohydrin)
C. SN1 on an alkyl halide
D. E2 elimination
Answer: B
Which type of reaction is saponification?
A. Formation of esters from acids
B. Base-catalyzed hydrolysis of esters to carboxylate salts and alcohols
C. Radical polymerization
D. Hydrogenation
Answer: B
In UV-visible spectroscopy, increased conjugation generally causes:
A. Hypsochromic shift (to shorter wavelength)
B. Bathochromic shift (to longer wavelength)
C. No change in λmax
D. Disappearance of peaks
Answer: B
Nanoparticles typically range in size from:
A. 1–100 nm
B. 1–100 μm
C. 100–1000 nm
D. 1–10 mm
Answer: A
Quantum size effects in nanoparticles cause:
A. Bulk properties only
B. Size-dependent optical and electronic properties
C. No change with size
D. Increased melting point always
Answer: B
Which type of isomerism arises from different connectivity of atoms?
A. Stereoisomerism
B. Structural (constitutional) isomerism
C. Conformational isomerism only
D. Optical isomerism only
Answer: B
The benzene ring has bond lengths that are:
A. Alternating single and double bond lengths equal to typical single/double values
B. All equal due to delocalized π system (intermediate between single and double)
C. All single bonds only
D. All triple bonds
Answer: B
Which reagent nitrates benzene to nitrobenzene?
A. HNO₃/H₂SO₄ (mixed acid)
B. Br₂/FeBr₃
C. HCl only
D. NaOH only
Answer: A
Friedel–Crafts alkylation requires which type of catalyst?
A. Lewis acid (e.g., AlCl₃)
B. Brønsted base only
C. Radical initiator only
D. None
Answer: A
Which substituent strongly deactivates an aromatic ring and directs meta substitution?
A. –OH
B. –CH₃
C. –NO₂
D. –OCH₃
Answer: C
Which of the following is an electrophile?
A. OH⁻
B. H⁺
C. CN⁻
D. NH₃
Answer: B
In a polar protic solvent, which SN mechanism is favored?
A. SN2
B. SN1 (because protic solvents stabilize carbocations and leaving groups)
C. E2 only
D. Radical substitution only
Answer: B
Which spectral technique gives information about hydrogen atoms’ chemical environment?
A. IR spectroscopy
B. ¹H NMR spectroscopy
C. Mass spectrometry
D. UV-Vis spectroscopy
Answer: B
A Michaels addition involves:
A. Nucleophilic addition to α,β-unsaturated carbonyl compounds (conjugate addition)
B. Radical chain propagation only
C. Electrophilic aromatic substitution
D. SN1 reactions only
Answer: A
Which is a common method to prepare alkenes from alcohols?
A. Hydration
B. Dehydration (acid-catalyzed elimination)
C. Hydrogenation
D. Oxidation only
Answer: B
Which of the following is the strongest acid?
A. Phenol
B. Ethanol
C. Acetic acid
D. Hydrochloric acid (in aqueous solution)
Answer: D
In coordination chemistry, ligands that bind through oxygen include:
A. CN⁻ only
B. H₂O and OH⁻ and acetate
C. CO only
D. NH₃ only
Answer: B
The 18-electron rule is most useful for predicting stability of complexes of:
A. Main group elements only
B. Transition metal complexes (especially low-spin, organometallic species)
C. Noble gases only
D. Alkali metals only
Answer: B
Which molecule is planar due to sp² carbons and conjugation?
A. Cyclohexane (chair)
B. Benzene
C. Ethane
D. Butane
Answer: B
Radical polymerization typically involves:
A. Ionic initiation only
B. Radical initiation, propagation, termination steps
C. Electrophilic aromatic substitution
D. Nucleophilic substitution
Answer: B
A sigma complex (arenium ion) in EAS is stabilized by:
A. Loss of aromaticity permanently
B. Resonance delocalization of the positive charge over the ring (temporary, until re-aromatization)
C. Formation of radicals only
D. Chelation with metals
Answer: B
Which oxidation state is common for iron in transition metal chemistry?
A. +1 only
B. +2 and +3 commonly
C. -1 only
D. +8 commonly
Answer: B
Which is a polar aprotic solvent that favors SN2 reactions?
A. Water
B. DMSO or DMF
C. Ethanol
D. Methanol
Answer: B
Which property increases as alkane chain length increases?
A. Volatility
B. Boiling point
C. Solubility in water
D. Vapor pressure
Answer: B
An E2 elimination requires:
A. A strong base and a good leaving group; concerted mechanism
B. Formation of carbocation intermediate
C. Free radical intermediates only
D. Metal catalysts always
Answer: A
Which reagent is commonly used to oxidize secondary alcohols to ketones?
A. NaBH₄
B. PCC or KMnO₄ (mild-to-strong oxidants)
C. H₂/Pd (reducing conditions)
D. LiAlH₄ (reducing)
Answer: B
The benzene ring undergoes substitution rather than addition because:
A. Addition is faster
B. Substitution preserves aromaticity while addition would destroy it
C. It has no π electrons
D. It is always reduced first
Answer: B
Which geometry is expected for square planar complexes?
A. Tetrahedral
B. Octahedral
C. Square planar (common for d8 complexes like Pt(II))
D. Linear only
Answer: C
Which is an example of an aromatic sextet?
A. Cyclobutadiene (4 π electrons)
B. Benzene (6 π electrons)
C. Cyclooctatetraene (8 π electrons)
D. Cyclopropene (2 π electrons)
Answer: B
Which of the following is a primary source of nanoparticles in nanochemistry labs?
A. Ball milling, sol–gel, chemical vapor deposition (CVD) and wet chemical synthesis
B. Distillation only
C. Simple filtration only
D. Sublimation of salts only
Answer: A
Which bond is stronger: C–C single or C=C double?
A. C–C single stronger
B. C=C double stronger (due to σ + π bonding)
C. They are equal
D. Depends on solvent only
Answer: B
What is a leaving group in substitution reactions?
A. A species that departs with its bonding electrons, often stable on its own (e.g., Cl⁻, Br⁻)
B. The incoming nucleophile
C. The solvent only
D. Always H⁺ only
Answer: A
The Hammett equation relates:
A. Reactivity in organic reactions to substituent electronic effects (σ constants)
B. Boiling point to molecular weight only
C. pH to temperature only
D. Solubility to polarity only
Answer: A
Which of the following is a common ligand that forms strong field complexes and can lead to low-spin configurations?
A. I⁻
B. CN⁻ and CO (strong field ligands)
C. H₂O (weak field commonly)
D. Br⁻
Answer: B
The primary product of ozonolysis of an alkene under reductive workup is:
A. Two carbonyl compounds (aldehydes/ketones) depending on substitution
B. Alcohols always
C. Alkanes only
D. Carboxylic acids always
Answer: A
Which reaction type is hydroboration–oxidation?
A. Converts alkenes to alcohols with anti-Markovnikov regiochemistry (syn addition)
B. Converts alkynes to alkanes only
C. Radical halogenation only
D. Nucleophilic substitution only
Answer: A
Which species has an unpaired electron?
A. Carbocation
B. Radical
C. Carbene only if singlet
D. Anion only
Answer: B
Which is true about diamagnetic complexes?
A. Have unpaired electrons
B. All electrons paired (no net magnetic moment)
C. Only paramagnetic species
D. Always colored only
Answer: B
Which type of reaction describes the conversion of an alcohol into an alkyl halide using PBr₃?
A. Oxidation
B. Substitution (nucleophilic substitution, often SN2 for primary/secondary)
C. Elimination only
D. Radical polymerization
Answer: B
Which is the correct order of bond strength (strongest to weakest) among C–X where X = F, Cl, Br, I?
A. C–I > C–Br > C–Cl > C–F
B. C–F > C–Cl > C–Br > C–I
C. All equal
D. Depends on temperature only
Answer: B
Which statement about nanoparticles is FALSE?
A. They often have high surface area to volume ratio
B. They may exhibit unique optical properties (e.g., plasmon resonance)
C. Their properties are identical to bulk materials always
D. Size can influence melting point and reactivity
Answer: C
Which reaction converts an aldehyde to a carboxylic acid under strong oxidation?
A. Reduction with NaBH₄
B. Oxidation with KMnO₄ or HNO₃ (or Tollens gives silver mirror for aldehydes)
C. Addition of HBr only
D. Hydrogenation only
Answer: B
In coordination complexes, ambidentate ligands can bind through:
A. Only one atom always
B. Two different atoms (e.g., SCN⁻ binds through S or N)
C. Only through oxygen always
D. Never form chelates
Answer: B
Which type of reaction is characteristic for carbonyls with α-hydrogens under basic conditions?
A. Aldol condensation (enolate chemistry)
B. Electrophilic aromatic substitution
C. Radical halogenation only
D. Free radical polymerization only
Answer: A
Which functional group has the general structure R–C(=O)–OH?
A. Ester
B. Carboxylic acid
C. Amide
D. Ketone
Answer: B
The main driving force in formation of micelles from nanoparticles in solution is:
A. Covalent bonding only
B. Minimizing free energy via hydrophobic effects and surface energy considerations
C. Increase in ionic strength only
D. Light absorption only
Answer: B
For benzene nitration, the nitronium ion (NO₂⁺) is generated by:
A. HCl only
B. Reaction of HNO₃ with H₂SO₄ (protonation/dehydration) producing NO₂⁺
C. NaOH only
D. Br₂/FeBr₃
Answer: B
Which method is used to determine particle size distribution in nanomaterials?
A. Dynamic light scattering (DLS)
B. TLC only
C. Boiling point measurement only
D. Recrystallization only
Answer: A
Which orbital diagram is correct for benzene’s π system?
A. Three bonding π molecular orbitals filled with six π electrons, and three antibonding empty
B. Only one bonding orbital filled with six electrons
C. All π orbitals antibonding
D. No π orbitals because only sigma bonds exist
Answer: A
Which of the following is a Lewis acid?
A. NH₃ (Lewis base)
B. AlCl₃ (accepts electron pair)
C. H₂O only
D. OH⁻ only
Answer: B
Which reaction type best describes the Wolff–Kishner reduction?
A. Reduction of carbonyl to alkane (removes carbonyl oxygen) under strongly basic, hydrazone conditions
B. Oxidation of alcohols
C. Radical halogenation only
D. Formation of esters only
Answer: A
Which metal commonly forms blue or green colored aqueous complexes?
A. Copper(II) (blue/green)
B. Sodium only
C. Potassium only
D. Calcium only
Answer: A
Which reagent converts carboxylic acids to esters (acid-catalyzed)?
A. Alcohol + acid catalyst (Fischer esterification)
B. Strong base only
C. H₂/Pd only
D. Ozone only
Answer: A
Which is true about π conjugation?
A. Decreases stability of a molecule always
B. Delocalization of electrons leads to stabilization and often changes in reactivity and spectroscopy
C. Only occurs in alkanes
D. Prevents any reactions from occurring
Answer: B
Which reaction mechanism describes electrophilic addition to conjugated dienes producing 1,2- and 1,4-products?
A. Radical chain only
B. Resonance-stabilized carbocation intermediate leading to both 1,2- and 1,4-addition products
C. SN2 only
D. None
Answer: B
Which is the major product when HBr adds to propene under peroxides (ROOR)?
A. 2-Bromopropane (Markovnikov)
B. 1-Bromopropane (anti-Markovnikov via radical addition)
C. 2-Propanol
D. No reaction
Answer: B
Which compound is aromatic by Hückel’s rule?
A. Cyclopentadienyl anion (6 π electrons)
B. Cyclobutadiene (4 π electrons)
C. Cyclohexadienyl cation (4 π electrons)
D. None
Answer: A
A sigma (σ) bond is formed by:
A. Side-to-side overlap of p orbitals
B. End-to-end overlap of orbitals along internuclear axis (s–s, s–p, p–p, sp–sp etc.)
C. Electrostatic attraction only
D. No orbital overlap
Answer: B
Which transition metal is commonly used in catalytic hydrogenation (heterogeneous catalyst)?
A. Pd, Pt, or Ni supported on carbon or other supports
B. Na only
C. Li only
D. K only
Answer: A
Which of the following describes a meso compound?
A. Always chiral and optically active
B. Has stereocenters but is achiral due to internal plane of symmetry
C. Only racemic mixtures are meso
D. Only compounds with no stereocenters
Answer: B
Which is the conjugate base of acetic acid (CH₃COOH)?
A. CH₃COOH₂⁺
B. CH₃COO⁻ (acetate)
C. CH₃CO⁺
D. CH₃⁻
Answer: B
Which factor most influences color in transition metal complexes?
A. d–d electronic transitions influenced by ligand field splitting (Δ) and ligands
B. Only ligand mass
C. Only ionic radii
D. Boiling point only
Answer: A
Which mechanism operates when an alkyl halide reacts with a strong nucleophile in a polar aprotic solvent at a primary center?
A. SN1
B. SN2 (favored)
C. E1 only
D. Free radical chain only
Answer: B
Which statement about nanomaterials toxicity is correct?
A. All nanomaterials are completely safe
B. Nanomaterials may exhibit unique biological interactions and require assessment; toxicity depends on size, shape, composition, and surface chemistry
C. Toxicity is independent of surface area
D. Only bulk materials are toxic
Answer: B
Which of the following is classified as an sp³ carbon?
A. Carbon in methane
B. Carbon in ethene double bond
C. Carbon in ethyne triple bond
D. Carbon in benzene ring (sp²)
Answer: A
Which reagent will oxidize primary alcohols to carboxylic acids under strong conditions?
A. PCC only (stops at aldehyde often)
B. KMnO₄ (strong oxidant)
C. NaBH₄ (reducing agent)
D. H₂/Pd (reducing)
Answer: B
Which of the following is an inert gas and not a transition metal?
A. Argon
B. Iron
C. Copper
D. Nickel
Answer: A
Which term describes movement of electrons around a conjugated ring distributing charge?
A. Resonance (delocalization)
B. Hyperconjugation only
C. Steric hindrance only
D. Ionic bonding only
Answer: A
Which reaction forms nitriles from alkyl halides via nucleophilic substitution?
A. Reaction with NaCN (SN2) to replace halide with CN group
B. Reaction with H₂O only
C. Reaction with NaBH₄ only
D. Reaction with HBr only
Answer: A
Which type of reaction is the Diels–Alder reaction?
A. [4+2] cycloaddition pericyclic reaction (concerted, stereospecific)
B. Radical polymerization only
C. SN1 only
D. E2 only
Answer: A
Which is an example of an ambident nucleophile?
A. CN⁻ (can attack through C or N)
B. OH⁻ only (single atom donor)
C. H⁻ only
D. Br⁻ only
Answer: A
Which property generally increases for nanoparticles compared to bulk material?
A. Density only
B. Surface area to volume ratio (increases)
C. Bulk melting point always increases
D. All mechanical properties identical
Answer: B
Which bond angle is expected in ethyne (sp carbon)?
A. 109.5°
B. 120°
C. 180°
D. 90°
Answer: C
Which reagent is used to convert an alkyl halide to an alkene via elimination?
A. Strong base like KOH or t-BuOK (E2 elimination)
B. NaBH₄ only
C. H₂/Pd only
D. NaCN only
Answer: A
Which species is a carbocation?
A. Cationic carbon with positive charge (e.g., R₃C⁺)
B. Radical with unpaired electron
C. Carbanion with negative charge
D. Neutral alkane only
Answer: A
Which compound shows cis–trans isomerism?
A. 2-Butene (cis/trans)
B. Ethane (no double bond)
C. 1-Butyne (triple bond)
D. Methane
Answer: A
Which of the following is a strong field ligand?
A. I⁻
B. CN⁻
C. Br⁻
D. Cl⁻
Answer: B
Which is the correct product when benzene undergoes chlorination with Cl₂/FeCl₃?
A. Chlorobenzene (substitution)
B. 1,2-dichloroethane (addition)
C. Benzene chloride addition product that destroys aromaticity permanently
D. No reaction
Answer: A
Which of the following best describes σ and π bonds in ethylene?
A. One σ and one π bond between the two carbons (σ from sp²–sp² overlap, π from p–p overlap)
B. Two σ bonds only
C. No π bonds
D. Triple bond between carbons
Answer: A
Which technique separates enantiomers using chiral stationary phases?
A. Gas chromatography on achiral column only
B. Chiral HPLC (high-performance liquid chromatography)
C. TLC only with achiral silica
D. Fractional distillation only
Answer: B
Which mechanism is involved when tertiary alkyl halides react with weak nucleophiles?
A. SN2 (favored for primary centers)
B. SN1 (favored for tertiary due to stable carbocation)
C. Radical substitution only
D. No reaction possible
Answer: B
What is the product of hydration of ethene in presence of acid (Markovnikov addition)?
A. Ethanol (CH₃CH₂OH)
B. Ethane
C. Acetaldehyde only
D. No reaction
Answer: A
Which of the following is a common reducing agent in organic chemistry?
A. KMnO₄
B. NaBH₄ (reduces carbonyls to alcohols)
C. HNO₃
D. O₃
Answer: B
Which factor stabilizes radicals?
A. Electron-withdrawing groups only
B. Resonance and alkyl substitution (tertiary radicals more stable than primary)
C. No effect of substitution
D. Only aromaticity stabilizes radicals
Answer: B
Which functional group is present in an amide?
A. R–C(=O)–NH–R (carbonyl bonded to nitrogen)
B. R–OH only
C. R–NH₂ only without carbonyl
D. R–COOR only
Answer: A
Which process is used to functionalize nanotubes or nanoparticles to increase solubility?
A. Surface functionalization (covalent or noncovalent) with polar groups
B. Distillation only
C. Sublimation only
D. Boiling only
Answer: A
Which is true about benzene’s resonance energy?
A. Benzene has no resonance stabilization
B. Benzene is stabilized by resonance compared to hypothetical localized 1,3,5-cyclohexatriene (it has resonance energy)
C. Resonance destabilizes benzene
D. Benzene is antiaromatic
Answer: B
Which reagent is used to brominate an alkane via radical halogenation under light?
A. Br₂/hν (light) producing alkyl bromide via radical mechanism
B. HBr/H₂O only
C. NaBr only
D. Br₂/FeBr₃ only (for aromatics)
Answer: A
Which of the following is NOT a typical property of transition metals?
A. Formation of colored compounds
B. Variable oxidation states
C. Formation of ionic salts only, never complexes
D. Catalytic properties
Answer: C
The catalytic converter in cars often uses which transition metals?
A. Platinum, rhodium, palladium (to catalyze oxidation/reduction of pollutants)
B. Sodium only
C. Potassium only
D. Calcium only
Answer: A
Which type of carbonyl compound gives a positive Tollens’ test?
A. Aldehydes (reduce Tollens’ reagent to metallic silver)
B. Ketones (generally negative)
C. Esters only
D. Ethers only
Answer: A
Which term describes replacement of H in benzene by another group?
A. Addition
B. Substitution (electrophilic aromatic substitution)
C. Polymerization only
D. Oxidation only
Answer: B
Which sample would show a strong, broad IR absorption around 1700 cm⁻¹?
A. Alcohol O–H stretch
B. Carbonyl C=O stretch (around 1700 cm⁻¹)
C. C–H stretch only
D. N–H stretch only
Answer: B
Which type of isomerism arises from different spatial arrangement due to hindered rotation?
A. Structural isomerism only
B. Conformational isomerism (e.g., staggered vs eclipsed)
C. Isotopic isomerism only
D. Chain isomerism only
Answer: B
Which organometallic reagent is sensitive to moisture and reacts vigorously with water?
A. Organolithium (R–Li) and Grignard reagents (R–MgX) — both are moisture-sensitive
B. NaCl only
C. KBr only
D. Ethanol only
Answer: A
Which bond fission is responsible for formation of carbocations?
A. Homolytic only
B. Heterolytic bond cleavage where leaving group leaves with electron pair producing carbocation
C. Radical formation only
D. No bond fission involved
Answer: B
A ligand that binds through nitrogen atoms (like NH₃) is called:
A. Oxo ligand only
B. Nitrogen donor ligand (amine ligand)
C. Carbonyl ligand only
D. Halide only
Answer: B
The phenomenon where electron density donation from σ bonds stabilizes adjacent carbocations is called:
A. Resonance only
B. Hyperconjugation
C. Aromaticity only
D. Induction only
Answer: B
Which of the following is a pericyclic reaction?
A. Diels–Alder cycloaddition
B. SN1 substitution only
C. Radical halogenation only
D. Nucleophilic acyl substitution only
Answer: A
Which is true about the Curie temperature of nanoparticles vs bulk?
A. Always higher for nanoparticles
B. Can differ due to size effects; magnetic properties can be size-dependent
C. Identical always
D. Not applicable to magnetic materials
Answer: B
Which compound is achiral despite having stereocenters (example)?
A. Meso-tartaric acid (has stereocenters but internal plane of symmetry)
B. Glyceraldehyde (chiral)
C. Lactic acid (chiral)
D. 2-Butanol (chiral)
Answer: A
Which reagent converts alkenes to vicinal dihalides?
A. Br₂ in CCl₄ (adds across double bond to give vicinal dibromides)
B. H₂O only
C. H₂/Pd only
D. NBS only
Answer: A
Which metal complex geometry is common for 6-coordinate complexes?
A. Tetrahedral only
B. Octahedral (common)
C. Square planar only
D. Linear only
Answer: B
Which of the following is a common technique for imaging nanoparticles?
A. Transmission electron microscopy (TEM)
B. TLC only
C. Boiling point measurement only
D. IR spectroscopy only
Answer: A
Which statement best describes resonance stabilization in benzene?
A. Electrons localized in alternating double bonds
B. Delocalized π electrons over the ring leading to extra stabilization (resonance energy)
C. No delocalization present
D. Only sigma bonds contribute to resonance
Answer: B
Which functional group is most susceptible to nucleophilic acyl substitution?
A. Ester, acid chloride, amide, anhydride (acyl derivatives)
B. Alkene only
C. Alkane only
D. Ether only
Answer: A
Which catalyst is typically used for hydroformylation (adding CO and H₂ across alkenes to form aldehydes)?
A. Rh or Co based complexes (e.g., HRh(CO)(PPh₃)₃)
B. NaCl only
C. Cu only
D. Fe only
Answer: A
Which of the following is true about aromatic heterocycles like pyrrole?
A. Pyrrole is aromatic with 6 π electrons including lone pair participation (actually pyrrole has 6 π electrons counting the lone pair of N in conjugation)
B. Pyrrole is antiaromatic
C. Pyrrole has no aromatic stabilization
D. None of the above
Answer: A
Which reagent removes protecting groups such as silyl ethers?
A. TBAF (tetrabutylammonium fluoride) commonly removes silyl protecting groups
B. NaBH₄ only
C. H₂ only
D. Ozone only
Answer: A
Which is a polar covalent bond example?
A. H–H (nonpolar)
B. C–O (polar covalent)
C. Na–Cl (ionic)
D. Metallic bonding only
Answer: B
Which of the following is a method to synthesize carboxylic acids?
A. Oxidation of primary alcohols or aldehydes (strong oxidants)
B. Hydrogenation of alkenes only
C. Free radical polymerization only
D. Grignard reagent with CO₂ followed by acidification
Answer: A
Which reaction type is characteristic of carbonyl compounds with no α-hydrogens (e.g., benzaldehyde) under base?
A. Aldol condensation requires α-hydrogen; without it no aldol formation from that carbonyl
B. Cannizzaro reaction (disproportionation of non-enolizable aldehydes under strong base)
C. Free radical substitution only
D. Polymerization only
Answer: B
Which is true about coordination number?
A. Number of ligands bound to metal center (can be > number of donor atoms if polydentate)
B. Number of electrons only
C. Always 6
D. Only used for main group elements
Answer: A
Which is an example of electrophilic addition to alkynes leading to Markovnikov product?
A. HBr addition to terminal alkyne producing vinyl halide then geminal dihalide under excess HBr
B. Nucleophilic addition only
C. Radical halogenation only
D. No reaction possible
Answer: A
Which factor affects catalytic activity of transition metals?
A. Electronic configuration, oxidation state, ligand environment, particle size (for supported catalysts)
B. Only color of metal
C. Only melting point
D. None of the above
Answer: A
Which bond is weaker: C–H in methane or C–C single bond?
A. C–H in methane ~439 kJ/mol; C–C ~347 kJ/mol — C–C generally weaker than C–H, so C–C is weaker.
B. C–H weaker than C–C
C. Both identical always
D. Depends only on solvent
Answer: A
Which reaction sequence converts an alkene to an alcohol via anti-Markovnikov addition?
A. Hydroboration–oxidation (BH₃/THF then H₂O₂, OH⁻) gives anti-Markovnikov alcohols
B. Acid-catalyzed hydration (Markovnikov)
C. Oxymercuration–demercuration (Markovnikov)
D. Hydrogenation only
Answer: A
Which metal is typically involved in redox enzymes like cytochromes?
A. Iron (Fe) in heme groups (Fe participates in redox)
B. Sodium only
C. Calcium only
D. Potassium only
Answer: A
In a free radical chain reaction, which step terminates the chain?
A. Propagation step only
B. Termination step where two radicals combine to form stable product (e.g., R• + R• → R–R)
C. Initiation only
D. No termination occurs
Answer: B
Which statement about resonance is true?
A. Resonance structures are real discrete species
B. Actual molecule is a resonance hybrid lower in energy than any single resonance structure
C. Resonance always increases reactivity dramatically
D. Resonance structures indicate different compounds existing in equilibrium
Answer: B
Which of the following is an alkylating agent that can add alkyl groups to nucleophiles?
A. Methyl iodide (MeI) via SN2 alkylation of nucleophiles
B. Water only
C. Oxygen only
D. Nitrogen only
Answer: A
Which property of nanoparticles is exploited in gold nanoparticle-based colorimetric assays?
A. Surface plasmon resonance leading to color changes with particle aggregation or size changes
B. Boiling point change only
C. Density change only
D. Magnetic susceptibility only
Answer: A
Which compound is most likely to undergo nucleophilic acyl substitution fastest?
A. Acid chloride (RCOCl) — most reactive
B. Amide (least reactive typically)
C. Ether only
D. Alkane only
Answer: A
Which reagent is used for the dehydration of alcohols to alkenes?
A. Strong acid like H₂SO₄ or H₃PO₄ and heat (E1/E2 depending on conditions)
B. NaBH₄ only
C. H₂ only
D. NaCl only
Answer: A
Which of the following stabilizes carbocations?
A. Electron-withdrawing substituents only
B. Electron-donating substituents and resonance (allylic, benzylic) stabilize carbocations
C. No substitution helps
D. Only hyperconjugation destabilizes carbocations
Answer: B
Which transition metal oxidation state is most common for titanium in TiO₂?
A. Ti(IV) (titanium +4 in TiO₂)
B. Ti(0) only
C. Ti(-II) only
D. Ti(II) only
Answer: A
Which type of spectroscopy measures vibrational transitions and functional groups?
A. IR spectroscopy (identifies functional groups via vibrational modes)
B. ¹H NMR only
C. Mass spectrometry only
D. UV-Vis only
Answer: A
Which reagent converts a carbonyl (ketone) to an alcohol via reduction?
A. NaBH₄ (reduces ketones to secondary alcohols)
B. PCC only (oxidant)
C. H₂O only
D. Br₂ only
Answer: A
Which of the following are characteristic of metallic bonding in transition metals?
A. Delocalized electrons giving conductivity and malleability
B. Only ionic interactions present
C. No delocalized electrons at all
D. Covalent bonds exclusively
Answer: A
Which of the following functional groups is basic in nature?
A. Amine (R–NH₂)
B. Carboxylic acid (acidic)
C. Ester (neutral typically)
D. Ketone (neutral)
Answer: A
Which reagent is commonly used to form an acetal from an aldehyde/ketone?
A. Alcohol under acid catalysis (protecting carbonyl as acetal)
B. Water only
C. NaBH₄ only
D. H₂ only
Answer: A
Which of the following statements about aromaticity is true?
A. All cyclic conjugated molecules are aromatic
B. Aromatic molecules follow Hückel’s rule (4n+2 π electrons) and are planar and conjugated
C. Antiaromatic compounds are especially stable
D. Aromaticity is irrelevant to reactivity
Answer: B
Which is true about the Bohr model and nanoparticles?
A. Quantum confinement — as particle size approaches exciton Bohr radius, discrete energy levels and bandgap changes occur (quantum size effects)
B. No size-dependent electronic changes occur
C. Nanoparticles behave like bulk irrespective of size
D. Bohr model only applies to hydrogen atom and has nothing to do with nanoparticles
Answer: A
Which reagent is used to brominate benzene under electrophilic aromatic substitution?
A. Br₂/FeBr₃ (or AlBr₃) to generate Br⁺ electrophile
B. Br₂ alone in dark only (no catalyst)
C. NBS only (for allylic bromination)
D. HBr only
Answer: A
Which of the following are considered hard acids/bases in HSAB theory?
A. H⁺ (hard acid) prefers hard bases like F⁻, OH⁻; soft acids like Pd²⁺ prefer soft bases like PPh₃, I⁻
B. All acids/bases are same in HSAB concept
C. Soft acids prefer hard bases always
D. HSAB is irrelevant to coordination chemistry
Answer: A
Which method is used to synthesize nanoparticles by bottom-up approach?
A. Chemical reduction of metal salts (wet chemical methods)
B. Hammering bulk material only
C. Sublimation of solids only
D. Filtration only
Answer: A
Which compound will show a positive 2,4-DNP test?
A. Aldehydes and ketones (carbonyl compounds with C=O) forming hydrazones (orange/red precipitate)
B. Alkanes only
C. Ethers only
D. Alkenes only
Answer: A
Which type of isomerism is exhibited by glucose and fructose?
A. Stereoisomerism only
B. Functional group isomerism (both C6H12O6 but differ in carbonyl position: glucose is an aldehyde, fructose is a ketone)
C. Structural isomerism only irrelevant
D. No isomerism
Answer: B
Which compound is a common reducing agent in organometallic chemistry?
A. LiAlH₄ (strong reducing agent)
B. NaCl only
C. KBr only
D. H₂O only
Answer: A
In electrophilic aromatic substitution, the first step is:
A. Loss of leaving group only
B. Attack of aromatic π system on electrophile to form sigma complex (arenium ion)
C. Nucleophilic attack on the ring only
D. Radical chain propagation only
Answer: B
Which of the following is a measure of catalytic activity for nanoparticles?
A. Turnover frequency (TOF) and turnover number (TON) measure catalytic activity and durability respectively
B. Boiling point only
C. Density only
D. Color only
Answer: A
Which reagent effects hydration of an alkyne to give a ketone (via Markovnikov addition)?
A. HgSO₄ in dilute H₂SO₄ (oxymercuration-type) leads to ketone after tautomerization
B. BH₃ only (gives anti-Markovnikov via hydroboration to aldehyde on terminal alkyne)
C. H₂/Pd only
D. Ozone only
Answer: A
Which of the following stabilizes metal nanoparticles against aggregation?
A. Capping agents or ligands (e.g., thiols, polymers, surfactants) that provide steric/electrostatic stabilization
B. No stabilization needed
C. Heating only
D. Strong acids only
Answer: A
Which of the following indicates presence of aromatic protons in ¹H NMR around 7–8 ppm?
A. Aliphatic protons only appear here
B. Aromatic protons typically resonate around 6.5–8 ppm in ¹H NMR depending on substitution
C. Only carboxyl protons appear at 7–8 ppm always
D. No pattern exists
Answer: B
Which is the product of the reaction between an acid chloride and an alcohol under basic conditions?
A. Ester (nucleophilic acyl substitution gives ester)
B. Amide only
C. Alkane only
D. No reaction occurs
Answer: A
Which of the following is a good leaving group?
A. OH⁻ (poor leaving group unless protonated)
B. Tosylate (OTs) — good leaving group after activation
C. H⁻ only
D. R– (carbanion) only
Answer: B
Which transition metal commonly forms tetrahedral complexes with d10 configuration (e.g., Zn²⁺, Cd²⁺)?
A. Zn²⁺ (d10) often forms tetrahedral complexes in many compounds
B. Fe³⁺ only
C. Ni²⁺ only
D. Cu²⁺ only
Answer: A
Which of the following reactions is concerted and stereospecific?
A. Diels–Alder cycloaddition (concerted pericyclic reaction, stereospecific)
B. SN1 (stepwise)
C. Radical chain termination only
D. Free radical halogenation only
Answer: A
Which property of nanoparticles makes them useful in drug delivery?
A. Tunable surface functionalization, small size for enhanced permeability and retention (EPR) effect, controlled release
B. Only high melting point
C. Only color changes
D. Only smell changes
Answer: A
Which step in the mechanism of electrophilic aromatic substitution regenerates aromaticity?
A. Formation of sigma complex only
B. Deprotonation of sigma complex to restore aromaticity (loss of H⁺)
C. Radical formation only
D. No regeneration needed
Answer: B
Which of the following is a chemical property of alkenes?
A. Undergo addition reactions (electrophilic addition) due to π bond reactivity
B. Only undergo substitution reactions like alkanes
C. Do not react at all
D. Always oxidize to inert compounds only
Answer: A
Which of the following best describes ligand field splitting energy (Δ) influence on color?
A. Magnitude of Δ determines wavelengths of light absorbed (hence color) for d–d transitions in transition metal complexes
B. Δ has no effect on color
C. Color determined only by molecular weight
D. Only solvent determines color ignoring Δ
Answer: A
Which is true about catalytic hydrogenation of benzene under standard conditions?
A. Benzene is readily hydrogenated under mild conditions to cyclohexane without strong catalysts/conditions
B. Hydrogenation of benzene requires strong conditions (high pressure, high temp, active catalyst) because of aromatic stabilization
C. Benzene cannot be hydrogenated under any condition
D. Hydrogenation always gives phenol instead
Answer: B
Which statement about nanomaterial surface chemistry is true?
A. Surface atoms have lower coordination leading to high reactivity; surface functionalization can tune solubility, reactivity, and biological interactions
B. Surface chemistry is irrelevant for nanoparticles
C. All nanoparticles are inert regardless of surface
D. Surface atoms behave identically to bulk atoms always
Answer: A

ANOTHER 100 QUESTIONS FOR PRACTICE

Which of the following best defines organic chemistry?
A. Study of salts and ionic compounds
B. Study of carbon-containing compounds and their reactions
C. Study of metallic elements only
D. Study of nuclear reactions
Answer: B
Which hybridization describes the carbon atom in methane (CH₄)?
A. sp
B. sp²
C. sp³
D. dsp³
Answer: C
The general formula for an alkane is
A. CnH2n+2
B. CnH2n
C. CnH2n−2
D. CnHn
Answer: A
Which functional group is present in ethanol?
A. Aldehyde
B. Ether
C. Hydroxyl (alcohol)
D. Carboxyl
Answer: C
Homolytic bond fission produces
A. Ions only
B. Radical species (each atom takes one electron)
C. A single heterolytic ion pair
D. No reactive intermediates
Answer: B
Benzene is aromatic because it is
A. Cyclic, conjugated and follows Hückel’s 4n+2 π-electron rule
B. Linear and saturated
C. Antiaromatic with 4 π electrons
D. A polymer of ethene units
Answer: A
Transition elements are typically characterized by
A. Filled s and p subshells only
B. Partially filled d orbitals and multiple oxidation states
C. Lack of d electrons entirely
D. Being inert gases
Answer: B
An electrophilic addition reaction is most commonly observed in
A. Alkanes under normal conditions
B. Alkenes where the π bond is attacked by electrophiles
C. Alkynes only when saturated
D. Aromatic rings without deactivation
Answer: B
Which IUPAC name is correct for CH₃CH₂CH₂OH?
A. Propan-1-ol
B. 2-Propanol
C. Propanal
D. Methoxyethane
Answer: A
The bond angle in ethene (C₂H₄) about each carbon is approximately
A. 109.5°
B. 120°
C. 180°
D. 90°
Answer: B
Which of the following is a structural isomer of butane (C₄H₁₀)?
A. 1-Butene
B. 2-Butanol
C. 2-Methylpropane (isobutane)
D. But-2-yne
Answer: C
Which reagent is commonly used to test for unsaturation (presence of C=C)?
A. Benedict’s reagent
B. Bromine in CCl₄ (color disappears if alkene present)
C. Tollen’s reagent
D. 2,4-DNP only
Answer: B
An ether functional group can be represented as
A. R–OH
B. R–O–R’
C. R–C≡O
D. R–COOH
Answer: B
Heterolytic fission of a C–Br bond typically yields
A. Two radicals
B. A carbocation (C⁺) and a bromide anion (Br⁻)
C. Two anions
D. A neutral molecule and a photon
Answer: B
Which product results from nitration of benzene (using HNO₃/H₂SO₄)?
A. Benzaldehyde
B. Nitrobenzene (–NO₂ substituted)
C. Aniline directly
D. Phenol
Answer: B
Which property is characteristic of transition metals compared to s-block metals?
A. Only form +1 oxidation state
B. Exhibit variable oxidation states and form colored complexes
C. Never form coordination compounds
D. Lack metallic bonding
Answer: B
A free radical chain reaction has three basic steps; which is NOT one of them?
A. Initiation
B. Propagation
C. Termination
D. Hydrolysis
Answer: D
Friedel–Crafts alkylation of benzene requires which catalyst?
A. H₂O only
B. AlCl₃ (Lewis acid)
C. NaOH strong base
D. KMnO₄ oxidant
Answer: B
The major product of hydrogenation of ethyne (acetylene) using H₂/Pd (excess) is
A. Ethene
B. Ethane
C. Methane
D. Benzene
Answer: B
In VSEPR theory, the geometry of methane is described as
A. Linear
B. Trigonal planar
C. Tetrahedral
D. Square planar
Answer: C
Which bond is strongest in terms of bond dissociation energy (typical)?
A. C–C single bond
B. C–H bond
C. C=C double bond (stronger than single but less than triple)
D. C≡C triple bond (strongest among them)
Answer: D
Which hydrocarbon is aromatic?
A. Cyclohexane
B. Benzene
C. 1,3-Butadiene
D. Cyclopentane
Answer: B
Which suffix is used for naming aldehydes in IUPAC nomenclature?
A. –ol
B. –one
C. –al
D. –oic acid
Answer: C
Carbocations are stabilized by which effect?
A. Electronegativity of hydrogen only
B. Inductive and hyperconjugation from alkyl substituents (tertiary most stable)
C. Presence of strong bases nearby always destabilizes them
D. Resonance never stabilizes carbocations
Answer: B
Which ligand is monodentate (binds through a single donor atom)?
A. Ethylenediamine (en)
B. Oxalate (C₂O₄²⁻)
C. Cyanide (CN⁻)
D. EDTA (hexadentate)
Answer: C
Electrophilic aromatic substitution on nitrobenzene is slowed because NO₂ is a
A. Strong activating, o/p-directing group
B. Strong deactivating, m-directing group
C. Radical initiator only
D. Metal chelator
Answer: B
Markovnikov’s rule predicts the regioselectivity of adding H–X to an alkene: the hydrogen attaches to the carbon with
A. Fewer hydrogens (forming more stable carbocation)
B. More hydrogens (forming more stable carbocation)
C. Equal hydrogens always
D. Only tertiary carbons regardless of structure
Answer: B
Which transition metal is commonly used as a hydrogenation catalyst in industry (e.g., catalytic hydrogenation)?
A. Sodium (Na)
B. Palladium (Pd) or platinum (Pt)
C. Neon (Ne)
D. Bromine (Br₂)
Answer: B
Which reaction type converts an alcohol into an alkene by removal of H and OH?
A. Oxidation
B. Elimination (dehydration)
C. Substitution only
D. Hydrogenation
Answer: B
The IUPAC name for CH₃–CH₂–Cl is
A. Chloroethane
B. Ethyl chloride (acceptable common name)
C. Both A and B (A is systematic)
D. Methyl chloride
Answer: C
Which statement about resonance in benzene is correct?
A. Benzene has alternating single and double bonds with distinct bond lengths
B. Benzene’s electrons are delocalized resulting in equal bond lengths and extra stability
C. Benzene is nonplanar and nonaromatic
D. Resonance does not affect benzene stability
Answer: B
A sigma (σ) bond is characterized by
A. Side-by-side overlap of p orbitals
B. Head-on overlap of orbitals along the internuclear axis
C. Being weaker than any pi bond
D. Only occurring in ionic bonding
Answer: B
Which hydrocarbon will undergo polymerization via free radical initiation most readily?
A. Ethene (ethylene)
B. Methane
C. Benzene under mild conditions
D. Carbon dioxide
Answer: A
Which reagent oxidizes primary alcohols to aldehydes (without further oxidation to acid) under controlled conditions?
A. KMnO₄ strongly under hot, acidic conditions (gives acid)
B. PCC (pyridinium chlorochromate) in CH₂Cl₂
C. H₂/Pd (hydrogenation catalyst)
D. NaBH₄ (a reducing agent)
Answer: B
Phenol is more acidic than ethanol because its conjugate base is
A. Less stabilized by resonance
B. Stabilized by resonance with the aromatic ring (delocalization of negative charge)
C. More basic than ethanol’s conjugate base
D. Unable to ionize in water
Answer: B
Which is a characteristic oxidation state range commonly found for transition metals?
A. Only +1 always
B. Multiple oxidation states often spanning +1 to +7 depending on the metal
C. Negative oxidation states exclusively
D. Zero only in all compounds
Answer: B
Which of the following is a nucleophile?
A. H⁺ (proton)
B. OH⁻ (hydroxide ion) — electron-rich and donates electrons to electrophiles
C. NO₂⁺ (nitronium ion) — strong electrophile
D. BF₃ (boron trifluoride) — Lewis acid
Answer: B
Which is a common feature of sp² hybridized carbon?
A. Tetrahedral geometry
B. Trigonal planar geometry with one unhybridized p orbital forming a π bond
C. Linear geometry only
D. No possibility of forming double bonds
Answer: B
In SN1 reactions, the rate-determining step involves
A. Concerted backside attack only
B. Formation of a carbocation intermediate by loss of leaving group (unimolecular)
C. Bimolecular collision between nucleophile and substrate
D. Radical formation always
Answer: B
Which hydrocarbon contains a triple bond?
A. Ethene
B. Ethyne (acetylene)
C. Ethane
D. Benzene
Answer: B
Which functional group is represented by –C(=O)–O–R?
A. Ester
B. Amide
C. Ether
D. Alcohol
Answer: A
The heat of hydrogenation of benzene is lower than expected for three isolated double bonds because benzene is
A. Less stable than expected
B. More stable (aromatic stabilization / resonance energy)
C. Not hydrogenated by H₂/Pd at all
D. A saturated hydrocarbon
Answer: B
Which is a typical product when toluene (methylbenzene) undergoes nitration under standard conditions?
A. p-Nitrotoluene and o-nitrotoluene (methyl is o/p-directing)
B. m-Nitrotoluene only exclusively
C. Only nitrobenzene without methyl involvement
D. Toluene is inert to nitration
Answer: A
Complex ions where ligands form coordinate covalent bonds to a central metal are called
A. Ionic salts only
B. Coordination complexes or coordination compounds (e.g., [Fe(CN)₆]³⁻)
C. Covalent network solids only
D. Radicals exclusively
Answer: B
Which bond fission is most likely to produce ionic intermediates?
A. Homolytic fission (radicals)
B. Heterolytic fission (ion pair formation)
C. Photolytic cleavage producing radicals exclusively
D. No bond fission produces ions ever
Answer: B
Which aromatic substitution is favored by a strongly activating group like –OH on benzene?
A. Meta substitution predominantly
B. Ortho and para substitution (–OH is o/p-directing activating)
C. Only C–C bond cleavage
D. Polymerization of benzene ring
Answer: B
Which of the following is a typical characteristic of first-row transition metals?
A. Completely inert with no color in compounds
B. Variable oxidation states and formation of colored complexes due to d–d transitions
C. Always monatomic gases
D. Never form coordination compounds
Answer: B
The reaction where two molecules combine to form one with loss of a small molecule (e.g., H₂O) is called
A. Addition
B. Elimination
C. Condensation (or dehydration)
D. Ionization only
Answer: C
Which of the following is a strong leaving group in nucleophilic substitution reactions?
A. OH⁻ in neutral conditions (poor leaving group unless protonated)
B. Br⁻ (good leaving group)
C. CH₃⁻ (very poor leaving group)
D. H⁻ (never a leaving group)
Answer: B
Which method is used to determine oxidation states and electron count in transition-metal complexes?
A. Ignoring ligands totally
B. Counting valence electrons and applying oxidation state bookkeeping rules (18-electron rule as guideline)
C. Using only atomic mass difference
D. Observing color only
Answer: B
Which hydrocarbon is most reactive toward electrophilic addition?
A. Alkane
B. Alkene (π bond provides electron density)
C. Aromatic benzene under mild conditions
D. Saturated cyclic alkane only
Answer: B
Which reagent is commonly used to perform oxidative cleavage of an alkene to carbonyl compounds?
A. O₃ followed by reductive workup (ozonolysis)
B. H₂/Pd catalytic hydrogenation
C. NaBH₄ reduction only
D. Nucleophilic substitution conditions
Answer: A
In benzene, each carbon is sp² hybridized; the unhybridized p orbitals overlap to form
A. σ bonds only
B. A continuous π system (delocalized above and below the ring)
C. Ionic bonds between carbons
D. No bonding interactions at all
Answer: B
Which of the following is a secondary alcohol?
A. CH₃CH₂OH (ethanol)
B. (CH₃)₂CHOH (isopropanol)
C. CH₃OH (methanol)
D. (CH₃)₃COH (tert-butanol)
Answer: B
Which statement about SN2 reactions is TRUE?
A. They proceed via carbocation intermediate
B. Rate depends on both substrate and nucleophile concentration (bimolecular) and proceed with backside attack (inversion)
C. They are favored by tertiary substrates
D. They never occur in aprotic solvents
Answer: B
Which type of bond is typically formed between a metal ion and a lone pair on a ligand (e.g., NH₃ → Cu²⁺)?
A. Ionic bond only
B. Coordinate (dative) covalent bond where ligand donates electron pair to metal
C. Metallic bonding exclusively
D. Purely hydrogen bonding
Answer: B
Which reagent can convert a primary alkyl halide into an alkene via E2 elimination when treated with a strong base?
A. Weak nucleophile in polar protic solvent
B. Strong bulky base like t-BuOK promoting elimination
C. H₂/Pd (reducing conditions)
D. Acidic hydration conditions only
Answer: B
Which functional group defines an amide?
A. R–CO–OH
B. R–CO–NH₂ (carbonyl attached to nitrogen)
C. R–OH only
D. R–O–R’ only
Answer: B
The Huckel rule for aromaticity applies to planar conjugated rings with _____ π electrons.
A. 4n (antiaromatic)
B. 4n+2 (aromatic)
C. Only 6 electrons always
D. 2n electrons only
Answer: B
Which transition metal complex geometry is common for d⁸ metal ions like Pt(II) and Ni(II)?
A. Tetrahedral exclusively
B. Square planar is common for many d⁸ complexes
C. Octahedral never occurs
D. Linear only
Answer: B
Which of these is an example of an electrophile?
A. OH⁻ (nucleophile)
B. H⁺ or Br⁺ species (electron-poor and accept electrons)
C. NH₃ (nucleophilic)
D. Cl⁻ (nucleophilic)
Answer: B
Which is true about cis–trans (geometric) isomerism in alkenes?
A. Occurs when each carbon of double bond has two identical substituents
B. Requires each double-bonded carbon to have two different substituents (no free rotation)
C. Is possible in all single bonds freely
D. Occurs only in aromatic systems
Answer: B
Which oxidation reaction is commonly used to oxidize a secondary alcohol to a ketone?
A. PCC (or Jones reagent or KMnO₄ under controlled conditions)
B. NaBH₄ (reduction reagent)
C. H₂/Pd (hydrogenation)
D. Ozonolysis of alkenes only
Answer: A
What product results from the complete catalytic hydrogenation of benzene under severe conditions?
A. Cyclohexane (hydrogenated aromatic ring)
B. Ethane
C. Toluene only
D. No change possible under any conditions
Answer: A
Which property of transition metals makes them good catalysts?
A. Lack of variable oxidation states
B. Ability to adopt multiple oxidation states and form transient complexes with reactants
C. Being nonreactive and inert always
D. Having only filled d orbitals so they cannot bind substrates
Answer: B
Which reaction type converts an alkyl halide to an alcohol using aqueous NaOH via nucleophilic substitution?
A. E1 elimination only
B. SN1 or SN2 substitution depending on substrate (primary usually SN2, tertiary SN1)
C. Radical polymerization only
D. Friedel–Crafts alkylation
Answer: B
Which molecule is the simplest aromatic heterocycle (contains a heteroatom in the ring)?
A. Cyclohexane
B. Pyridine (C₅H₅N) — aromatic heterocycle with a nitrogen atom
C. Benzene only
D. Furan never aromatic
Answer: B
A common test to distinguish between aldehydes and ketones is Tollen’s reagent which gives a silver mirror with
A. Ketones only
B. Aldehydes (reducing agents)
C. Both aldehydes and ketones equally
D. Alcohols only
Answer: B
Radical halogenation (e.g., chlorine with hv) of alkanes is controlled by which factors?
A. Only nucleophilicity matters
B. Bond dissociation energies and radical stability (tertiary H abstraction favored)
C. Only solvent polarity
D. Aromaticity of substrate only
Answer: B
Which statement about benzene derivatives is TRUE?
A. Electron-donating substituents deactivate the ring toward electrophilic substitution
B. Electron-withdrawing substituents deactivate the ring and often direct meta substitution
C. All substituents direct ortho positions exclusively
D. Substituents never influence regiochemistry
Answer: B
Which is a typical ligand that can donate two pairs of electrons (bidentate)?
A. NH₃ (monodentate)
B. Ethylenediamine (en) — bidentate ligand binds through two nitrogens
C. Cl⁻ always monodentate only
D. CO only forms triple bonds with metal
Answer: B
Which reaction converts alkenes to alcohols under acid-catalyzed hydration?
A. Addition of H₂ across π bond without regiochemistry
B. Electrophilic addition of H⁺ then nucleophilic attack by H₂O (Markovnikov addition)
C. SN2 substitution of alkene carbon only
D. Radical polymerization
Answer: B
The mechanism that explains electrophilic aromatic substitution involves which intermediate?
A. Carbocation only unrelated to ring
B. Arenium ion (sigma complex / arenium cation) where aromaticity is temporarily lost
C. Radical anion always
D. No intermediate—concerted process only
Answer: B
Which gas is commonly evolved when carboxylic acids react with strong bases and carbonates?
A. Oxygen
B. Carbon dioxide (CO₂) from acid + carbonate reaction
C. Nitrogen gas only
D. Hydrogen only
Answer: B
Which of the following is a tertiary alkyl halide suitable for SN1 reactions but poor for SN2?
A. 1-Bromopropane (primary)
B. 2-Bromobutane (secondary)
C. 2-Bromo-2-methylpropane (tert-butyl bromide) — tertiary, stabilizes carbocation (SN1)
D. Methyl chloride (primary)
Answer: C
Which reagent would selectively reduce a nitro group (–NO₂) to an amine (–NH₂) under catalytic hydrogenation?
A. H₂/Pd or H₂/Ni under suitable conditions (reducing agent with catalyst)
B. KMnO₄ strong oxidant only
C. PCC oxidation conditions only
D. Na₂Cr₂O₇ (oxidizer)
Answer: A
Which term describes ligands that can bind through multiple donor atoms, increasing complex stability (chelate effect)?
A. Monodentate only
B. Bidentate or polydentate (chelate ligands like en, EDTA)
C. Noble gas ligands only
D. Anionic only regardless of denticity
Answer: B
Which of the following is an example of an electrophilic addition to an alkene that occurs via a cyclic bromonium ion intermediate?
A. Hydroboration–oxidation exclusively
B. Halogenation (addition of Br₂ across C=C) proceeding via bromonium ion intermediate
C. Radical polymerization always
D. SN2 substitution on saturated carbon only
Answer: B
Which reaction type increases saturation (adds hydrogen) across a C=C bond?
A. Oxidation
B. Hydrogenation (addition of H₂ across double bond)
C. Elimination
D. Substitution only
Answer: B
Which functional group undergoes nucleophilic acyl substitution reactions readily?
A. Carboxylic acid derivatives (acid chlorides, esters, amides) — especially acid chlorides
B. Alkenes only
C. Ethers only
D. Alkanes only
Answer: A
Which statement about coordination number is TRUE?
A. It is always equal to oxidation state
B. It is the number of ligand donor atoms directly bonded to the central metal ion (e.g., 6 in octahedral complexes)
C. It never exceeds 2
D. It only applies to organic molecules, not metal complexes
Answer: B
Which reaction converts an alkyl benzene side chain to benzoic acid (oxidation) when strong oxidants are used?
A. Hydrogenation of aromatic ring only
B. Oxidation of benzylic C–H (requires at least one benzylic hydrogen) to carboxylic acid (e.g., toluene → benzoic acid with KMnO₄)
C. Nitration exclusively
D. Halogenation at meta position only
Answer: B
Which is produced by acid-catalyzed hydration of 2-methylpropene (isobutene) under Markovnikov conditions?
A. 2-Methyl-2-propanol (tert-butanol)
B. 2-Methyl-1-propanol only
C. Isobutane always
D. No reaction at all
Answer: A
Which is the correct description of aromaticity in heterocycles like pyrrole?
A. Pyrrole is aromatic due to a 6 π-electron system where the nitrogen lone pair contributes to conjugation (4n+2 rule)
B. Pyrrole is nonaromatic always
C. Heterocycles cannot be aromatic
D. Pyrrole is antiaromatic only
Answer: A
Which reagent is commonly used to convert an alcohol into a tosylate (good leaving group) without inversion of configuration?
A. p-Toluenesulfonyl chloride (TsCl) with pyridine (forms tosylate)
B. HBr directly always (causes substitution and possible inversion)
C. NaBH₄ (reducing agent)
D. KMnO₄ only (oxidation)
Answer: A
Which of the following describes a catalytic cycle often used by transition metal catalysts?
A. No change in oxidation state during catalysis always
B. Sequence of oxidative addition, ligand substitution, reductive elimination steps (common pattern)
C. Catalysts consumed in stoichiometric amounts only
D. Only radical chain mechanisms ever occur with metals
Answer: B
Which is the major product of electrophilic addition of HBr to propene in the presence of peroxides (anti-Markovnikov)?
A. 2-Bromopropane (Markovnikov product)
B. 1-Bromopropane (anti-Markovnikov due to radical mechanism)
C. Propane only
D. Bromobenzene always
Answer: B
Which method separates compounds based on differences in boiling point and is useful for purifying volatile organic liquids?
A. Distillation (fractional or simple depending on boiling point differences)
B. Chromatography never useful for liquids
C. Titration only
D. Filtration of gases exclusively
Answer: A
Which of the following is a polar aprotic solvent that often accelerates SN2 reactions?
A. Water (polar protic)
B. DMSO (dimethyl sulfoxide) or DMF (polar aprotic)
C. Hexane (nonpolar)
D. Methanol (protic)
Answer: B
Which species is aromatic: cyclopentadienyl anion (C₅H₅⁻) or cyclopentadienyl cation (C₅H₅⁺)?
A. Both equally aromatic
B. Cyclopentadienyl anion (6 π electrons, aromatic) while cation is antiaromatic (4 π)
C. Cation aromatic, anion antiaromatic always
D. Neither can be aromatic ever
Answer: B
Which reagent is commonly used for the oxidation of a primary alcohol all the way to carboxylic acid?
A. PCC (stops at aldehyde under mild conditions)
B. KMnO₄ or Jones reagent (CrO₃/H₂SO₄) strong oxidants convert to carboxylic acids
C. NaBH₄ (reducing agent)
D. H₂/Pd (hydrogenation)
Answer: B
Which is a common feature of coordination compounds that exhibit geometric isomerism (cis/trans)?
A. Only linear complexes show cis/trans isomerism
B. Square planar complexes (e.g., [Pt(NH₃)₂Cl₂]) can show cis/trans isomers
C. Octahedral complexes never show isomerism
D. Monodentate ligands cannot produce isomers
Answer: B
Which reaction type commonly forms carbon–carbon bonds in organic synthesis?
A. Aldol condensation (enolate chemistry) and Grignard additions (RMgX forming C–C bonds)
B. Only oxidation reactions form C–C bonds always
C. Hydrogenation forms C–C bonds too
D. Halogenation always forms C–C bonds
Answer: A
UV–Vis spectroscopy of transition metal complexes often shows colored solutions due to
A. π→π* transitions only in ligands always
B. d–d transitions or charge-transfer transitions involving d electrons of metal and ligand
C. No electronic transitions possible in d-block metals
D. Only IR vibrations produce color
Answer: B
Which of the following is TRUE for addition polymerization of ethene?
A. Monomers join without the loss of small molecules to form polyethylene (C–C chain) via radical, anionic or coordination mechanisms
B. Polymerization always produces only natural polymers like proteins
C. Addition polymerization cannot produce high molecular weight polymers
D. Polymerization consumes catalysts in stoichiometric amounts only
Answer: A
Which species is the conjugate base of acetic acid (CH₃COOH)?
A. CH₃COOH itself only
B. CH₃COO⁻ (acetate ion)
C. H₃O⁺ only
D. CH₃⁻ (methyl anion)
Answer: B
In aromatic electrophilic substitution, a strong activating ortho/para director will
A. Increase reaction rate and direct incoming electrophile to ortho and para positions
B. Decrease reaction rate and direct meta only
C. Prevent any substitution entirely
D. Always remove aromaticity permanently
Answer: A
Which reagent is commonly used to prepare Grignard reagents (RMgX) from alkyl halides?
A. Aqueous HCl
B. Magnesium metal in dry ether (anhydrous conditions)
C. Sodium hydroxide in water
D. Water as solvent always
Answer: B
Which is the correct IUPAC name for the compound with formula CH₃–CH(CH₃)–CH₂–CH₃?
A. 2-Methylbutane
B. Butane always
C. 3-Methylpropane only
D. Pentane only
Answer: A
Which reaction type involves the removal of two substituents from adjacent carbons to form a double bond?
A. Addition reaction
B. Elimination (e.g., dehydrohalogenation, E2)
C. Substitution only
D. Radical halogenation
Answer: B

Leave a Reply Cancel reply

Chat With Us?

error: Emmy is Sorry Bruh !!