Organic Chemistry — Part 2: 34 MCQs with Explanations
34 intermediate organic chemistry MCQs with answers and explanations for MDCAT, FSc, PPSC preparation.
34
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Intermediate
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4
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51
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Intermediate MDCAT FSc PPSC FPSC
Last updated: Oct 13, 2026
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Q1 of 34
Which one is an example of an addition polymer?
Correct Answer: Option B — Polythene
Detailed Academic Explanation:
Addition polymers are formed by the repeated addition of monomer units without the elimination of any by-product. Polythene is made by the addition polymerization of ethene monomers.
💡 Key Conceptual Anchor:
Organic Chemistry
Q2 of 34
The IUPAC name of CH₃-O-C₂H₅ is:
Correct Answer: Option B — Methoxy ethane
Detailed Academic Explanation:
According to IUPAC nomenclature for ethers, the larger alkyl group is considered the parent alkane, and the smaller alkoxy group is named as a substituent. CH₃-O- is methoxy, attached to ethane (C₂H₆), so the name is methoxyethane.
💡 Key Conceptual Anchor:
Organic Chemistry
Q3 of 34
The reaction of an alkene with HBr in the presence of peroxide follows which mechanism?
Correct Answer: Option D — Anti-Markovnikov's rule (Free radical)
Detailed Academic Explanation:
In the presence of peroxides, the addition of HBr to an alkene follows a free radical mechanism that goes against Markovnikov's rule. The bromine atom adds to the less substituted carbon, resulting in anti-Markovnikov addition.
💡 Key Conceptual Anchor:
Organic Chemistry
Q4 of 34
The empirical formula of benzene is:
Correct Answer: Option A — CH
Detailed Academic Explanation:
The molecular formula of benzene is C₆H₆. The simplest whole number ratio of C to H is 1:1, so its empirical formula is CH.
💡 Key Conceptual Anchor:
Organic Chemistry
Q5 of 34
The functional group -CO- represents:
Correct Answer: Option C — Ketone
Detailed Academic Explanation:
The carbonyl group (C=O) when bonded to two carbon atoms is called a ketone. The general formula for a ketone is R-CO-R'. Acetone (CH₃-CO-CH₃) is the simplest example.
💡 Key Conceptual Anchor:
Organic Chemistry
Q6 of 34
The functional group present in alcohols is:
Correct Answer: Option C — -OH
Detailed Academic Explanation:
Alcohols contain hydroxyl group (-OH) attached to sp³-hybridized carbon atom.
💡 Key Conceptual Anchor:
Organic Chemistry
Q7 of 34
Which alcohol is secondary?
Correct Answer: Option C — (CH₃)₂CHOH
Detailed Academic Explanation:
(CH₃)₂CHOH has -OH group attached to carbon bonded to two other carbons ⇒ secondary alcohol.
💡 Key Conceptual Anchor:
Organic Chemistry
Q8 of 34
The reaction of alcohol with carboxylic acid in presence of acid catalyst produces:
Tollens' reagent [Ag(NH₃)₂]⁺ oxidizes aldehydes to carboxylates, producing silver mirror; ketones do not react.
💡 Key Conceptual Anchor:
Organic Chemistry
Q10 of 34
The functional group in carboxylic acids is:
Correct Answer: Option C — -COOH
Detailed Academic Explanation:
Carboxylic acids contain carboxyl group (-COOH).
💡 Key Conceptual Anchor:
Organic Chemistry
Q11 of 34
Esterification is an example of:
Correct Answer: Option A — Nucleophilic substitution
Detailed Academic Explanation:
Acid-catalyzed esterification involves nucleophilic attack of alcohol oxygen on protonated carbonyl carbon (addition-elimination mechanism).
💡 Key Conceptual Anchor:
Organic Chemistry
Q12 of 34
The functional group in amines is:
Correct Answer: Option D — -NH₂
Detailed Academic Explanation:
Amines contain amino group (-NH₂, -NHR, or -NR₂).
💡 Key Conceptual Anchor:
Organic Chemistry
Q13 of 34
Hinsberg's test is used to distinguish between:
Correct Answer: Option B — Primary, secondary and tertiary amines
Detailed Academic Explanation:
Hinsberg's test uses benzenesulfonyl chloride to differentiate 1°, 2°, and 3° amines based on solubility of products.
💡 Key Conceptual Anchor:
Organic Chemistry
Q14 of 34
Benzene undergoes electrophilic substitution rather than addition because:
Correct Answer: Option B — Addition would destroy aromaticity
Detailed Academic Explanation:
Addition reactions would disrupt benzene's aromatic sextet (resonance stabilization energy ~150 kJ/mol), making substitution energetically favorable.
💡 Key Conceptual Anchor:
Organic Chemistry
Q15 of 34
Teflon is polymer of:
Correct Answer: Option D — Tetrafluoroethene
Detailed Academic Explanation:
Teflon (PTFE): n CF₂=CF₂ → [─CF₂─CF₂─]_n
💡 Key Conceptual Anchor:
Organic Chemistry
Q16 of 34
Which is a biodegradable polymer?
Correct Answer: Option C — PHBV
Detailed Academic Explanation:
PHBV (poly-β-hydroxybutyrate-co-β-hydroxyvalerate) is biodegradable polyester produced by bacteria.
💡 Key Conceptual Anchor:
Organic Chemistry
Q17 of 34
BOD (Biochemical Oxygen Demand) measures:
Correct Answer: Option B — Organic pollution in water
Detailed Academic Explanation:
BOD measures oxygen required by microorganisms to decompose organic matter in water; high BOD indicates severe organic pollution.
💡 Key Conceptual Anchor:
Organic Chemistry
Q18 of 34
Which polymer is used in non-stick cookware?
Correct Answer: Option C — Teflon
Detailed Academic Explanation:
Teflon (PTFE) has very low coefficient of friction and high heat resistance, ideal for non-stick coatings.
💡 Key Conceptual Anchor:
Organic Chemistry
Q19 of 34
Rancidity of fats is due to:
Correct Answer: Option B — Oxidation
Detailed Academic Explanation:
Rancidity results from oxidative degradation of unsaturated fatty acids producing aldehydes/ketones with unpleasant odors.
💡 Key Conceptual Anchor:
Organic Chemistry
Q20 of 34
Cracking of petroleum is done to:
Correct Answer: Option B — Increase yield of gasoline
Detailed Academic Explanation:
Cracking breaks large hydrocarbon molecules into smaller, more valuable ones (e.g., gasoline range C₅-C₁₀) using heat/catalyst.
💡 Key Conceptual Anchor:
Organic Chemistry
Q21 of 34
The compound that causes knocking in engines is:
Correct Answer: Option B — n-Heptane
Detailed Academic Explanation:
n-Heptane has poor antiknock properties (octane number 0); branched/aromatic hydrocarbons resist knocking better.
💡 Key Conceptual Anchor:
Organic Chemistry
Q22 of 34
Which is NOT a fossil fuel?
Correct Answer: Option D — Wood
Detailed Academic Explanation:
Wood is biomass fuel, not fossil fuel. Fossil fuels (coal, petroleum, natural gas) formed from ancient buried organic matter over millions of years.
💡 Key Conceptual Anchor:
Organic Chemistry
Q23 of 34
The functional group in ethers is:
Correct Answer: Option C — -O-
Detailed Academic Explanation:
Ethers contain oxygen atom bonded to two alkyl/aryl groups (R-O-R').
💡 Key Conceptual Anchor:
Organic Chemistry
Q24 of 34
The compound that gives positive Lucas test immediately is:
Correct Answer: Option C — Tertiary alcohol
Detailed Academic Explanation:
Lucas reagent (ZnCl₂/HCl): tertiary alcohols form turbidity immediately; secondary within 5-10 min; primary no reaction at room temperature.
💡 Key Conceptual Anchor:
Organic Chemistry
Q25 of 34
The reaction of aldehyde with hydroxylamine gives:
Correct Answer: Option A — Oxime
Detailed Academic Explanation:
R-CHO + H₂NOH → R-CH=N-OH (aldoxime) + H₂O.
💡 Key Conceptual Anchor:
Organic Chemistry
Q26 of 34
The polymer used in bulletproof vests is:
Correct Answer: Option B — Kevlar
Detailed Academic Explanation:
Kevlar (aramid fiber) has high tensile strength due to hydrogen bonding between polymer chains, used in bulletproof vests.
💡 Key Conceptual Anchor:
Organic Chemistry
Q27 of 34
The compound used as insecticide is:
Correct Answer: Option C — Both A and B
Detailed Academic Explanation:
DDT (dichlorodiphenyltrichloroethane) and BHC (benzene hexachloride) are organochlorine insecticides (now restricted due to environmental persistence).
💡 Key Conceptual Anchor:
Organic Chemistry
Q28 of 34
The functional group in amides is:
Correct Answer: Option B — -CONH₂
Detailed Academic Explanation:
Amides contain carbonyl group bonded to nitrogen: -CONH₂ (primary), -CONHR (secondary), -CONR₂ (tertiary).
💡 Key Conceptual Anchor:
Organic Chemistry
Q29 of 34
The fraction of petroleum with lowest boiling point is: