JENPAS UG 2025 Organic Chemistry Important Questions with Answers

The IUPAC name of CH3–CH=CH2 is

a) Propane

b) Propene

c) Propanol

d) Propyne

Propene

Which of the following has the highest boiling point?

a) Butane

b) Butanol

c) Butanal

d) Butanone

Butanol

Which of the following shows resonance?

a) CH4

b) CO2

c) Benzene

d) C2H6

Benzene

Which is the most stable carbocation?

a) CH₃⁺

b) 1° carbocation

c) 2° carbocation

d) 3° carbocation

3° carbocation

Which type of isomerism is shown by C2H6O?

a) Structural isomerism

b) Optical isomerism

c) Geometrical isomerism

d) Chain isomerism

Structural isomerism

Electrophiles are

a) Electron rich species

b) Electron deficient species

c) Neutral species

d) Radicals only

Electron deficient species

The order of stability of carbocations is

a) 1° > 2° > 3°

b) 3° > 2° > 1°

c) 2° > 3° > 1°

d) 3° > 1° > 2°

3° > 2° > 1°

The general formula of alkanes is

a) CnH2n

b) CnH2n+2

c) CnH2n–2

d) CnHn

CnH2n+2

Which test is used to distinguish alkanes from alkenes?

a) Iodoform test

b) Tollen’s test

c) Bromine water test

d) Fehling’s test

Bromine water test

The major product of the reaction of 2-butene with HBr in presence of peroxide is

a) 2-bromobutane

b) 1-bromobutane

c) 3-bromobutane

d) 2,3-dibromobutane

1-bromobutane

Benzene undergoes which type of reaction predominantly?

a) Addition

b) Elimination

c) Substitution

d) Oxidation

Substitution

The monomer of polystyrene is

a) Ethene

b) Propene

c) Styrene

d) Vinyl chloride

Styrene

Ethyl alcohol reacts with sodium to liberate

a) HCl

b) H2

c) CO2

d) O2

H2

Phenol gives violet colour with

a) FeCl3

b) Br2

c) HNO3

d) NaOH

FeCl3

In Friedel–Crafts alkylation, the catalyst used is:

a) HCl

b) AlCl₃

c) NaOH

d) H₂SO₄

AlCl₃

Lucas test is used to distinguish between

a) Aldehydes and ketones

b) 1°, 2°, and 3° alcohols

c) Alkanes and alkenes

d) Phenols and alcohols

1°, 2°, and 3° alcohols

Formaldehyde is represented as

a) CH3CHO

b) HCHO

c) CH3COCH3

d) HCOOH

HCHO

Fehling’s solution is used to detect

a) Aromatic ketones

b) Aromatic aldehydes

c) Aliphatic aldehydes

d) Alcohols

Aliphatic aldehydes

The product formed when acetic acid reacts with ethanol in presence of conc. H2SO4 is

a) Acetone

b) Ethyl acetate

c) Acetaldehyde

d) Methyl alcohol

Ethyl acetate

Which one gives effervescence with NaHCO₃ solution?

a) Phenol

b) Alcohol

c) Carboxylic acid

d) Aldehyde

Carboxylic acid

Which compound gives a silver mirror test?

a) Ketone

b) Aldehyde

c) Ester

d) Ether

Aldehyde

Which of the following is optically active?

a) 2-Butanol

b) Ethanol

c) Propanol

d) Acetone

2-Butanol

The monomer of proteins is

a) Glucose

b) Amino acid

c) Fatty acid

d) Nucleotide

Amino acid

Which vitamin is fat-soluble?

a) Vitamin B

b) Vitamin C

c) Vitamin D

d) Vitamin H

Vitamin D

Which of the following is a functional isomer of ethanol?

a) Dimethyl ether

b) Propanol

c) Butanol

d) Ethanal

Dimethyl ether

Which reagent is used to distinguish between alkene and alkyne?

a) Tollen’s reagent

b) Bromine water

c) Baeyer's reagent (alkaline KMnO₄)

d) Fehling’s solution

Baeyer's reagent

Which reagent converts alcohol to aldehyde?

a) LiAlH₄

b) PCC (Pyridinium chlorochromate)

c) H₂ / Pt

d) HI

PCC

The sugar present in DNA is

a) Glucose

b) Ribose

c) Deoxyribose

d) Fructose

Deoxyribose

Some Basic Principles of Organic Chemistry

• Classification of organic compounds
• Homologous series & nomenclature (IUPAC rules)
• Hybridization (sp, sp², sp³) in organic compounds
• Resonance & hyperconjugation
• Inductive, mesomeric, electromeric effects
• Carbocations, carbanions, free radicals, carbenes
• Acidic & basic strength of organic compounds

Hydrocarbons

• Alkanes (general methods of preparation, substitution reactions)
• Alkenes (preparation, addition reactions, Markovnikov’s rule, peroxide effect)
• Alkynes (preparation & reactions)
• Aromatic hydrocarbons (benzene structure, aromaticity, electrophilic substitution: nitration, sulphonation, halogenation, Friedel–Crafts alkylation/acylation)

Haloalkanes & Haloarenes

• SN1 & SN2 reactions
• Elimination reactions (E1, E2)
• Uses of haloalkanes & haloarenes

Alcohols, Phenols, and Ethers

• Preparation & properties of alcohols (oxidation, esterification, dehydration)
• Phenols (acidity, electrophilic substitution, Kolbe’s & Reimer–Tiemann reactions)
• Ethers (cleavage by HI)

Aldehydes, Ketones, and Carboxylic Acids

• Nucleophilic addition reactions (HCN, NaHSO₃, Grignard)
• Aldol condensation, Cannizzaro reaction, haloform test
• Carboxylic acids: acidity, esterification, decarboxylation

Amines

• Classification & basicity of amines
• Preparation (reduction of nitro compounds, Hoffmann bromamide reaction)
• Diazonium salts & their reactions

Biomolecules

• Carbohydrates (glucose, fructose, cyclic structure)
• Proteins (α-helix, β-sheet, denaturation)
• Vitamins & nucleic acids basics

Polymers & Chemistry in Everyday Life

• Types of polymers (addition, condensation, natural, synthetic)
• Important polymers: PVC, Nylon, Bakelite, Teflon
• Drugs: analgesics, antibiotics, antiseptics