Every Isomerism question asked in JEE Main and JEE Advanced across the last 186 papers — 56 questions, each with its correct answer. Free to read, no account needed.
Questions
56
Papers it appeared in
51/186
Appearance rate
27%
All 56 Isomerism questions
Most recent papers first.
Q1·ChemistrySingle correctJEE Advanced 2026
Considering LiBH4 reduces an ester group to the corresponding alcohol and does not reduce a carboxylic acid group, the correct statement about the major products P, Q, R and S is
(A)P & Q are identical, and R & S are diastereomers.
(B)P & Q are diastereomers, and R & S are identical.
(C)P & Q are diastereomers, and R & S are diastereomers.
(D)P & Q are identical, and R & S are identical.
Q2·ChemistrySingle correctJEE Main 2026
Given below are two statements:
Statement I: 2,6-diethylcyclohexanone and 6-methyl-2-n-propylcyclohexanone are metamers.
Statement II: 2,2,6,6-tetramethylcyclohexanone exhibits keto-enol tautomerism.
In the light of the above statements, choose the correct answer from the options given below
(A)Both Statement I and Statement II are true
(B)Both Statement I and Statement II are false
(C)Statement I is true but Statement II is false
(D)Statement I is false but Statement II is true
Q3·ChemistrySingle correctJEE Main 2026
Identify correct statement from the following :
A. Propanal and propanone are functional isomers.
B. Ethoxyethane and methoxypropane are metamers.
C. But-2-ene shows optical isomerism.
D. But-1-ene and but-2-ene are functional isomers.
E. Pentane and 2, 2-dimethyl propane are chain isomers.
Choose the correct answer from the options given below :
(A)B, C and D only
(B)A, B and C only
(C)A, B and E only
(D)C, D and E only
Q4·ChemistrySingle correctJEE Main 2026
Match List-I (Pair of Compounds) with List-II (Type of Isomers). Choose the correct answer from the options given below:
Pair of Compounds
Type of Isomers
A.2-Methylpropene and but-1-ene
I.Stereoisomers
B.Cis-but-2-ene and trans-but-2-ene
II.Position isomers
C.2-Butanol and diethyl ether
III.Chain isomers
D.But-1-ene and but-2-ene
IV.Functional group isomers
(A)A-III, B-I, C-IV, D-II
(B)A-III, B-I, C-II, D-IV
(C)A-I, B-IV, C-III, D-II
(D)A-II, B-I, C-IV, D-III
Q5·ChemistryIntegerJEE Main 2025
The total number of structural isomers possible for the substituted benzene derivatives with the molecular formula C9H12 is __________.
Q6·ChemistrySingle correctJEE Main 2025
Given below are two statements: Statement (I): the two compounds shown in the figure are isomeric compounds. Statement (II): the two amines shown in the figure are functional group isomers. In the light of the above statements, choose the correct answer from the options given below:
(A)Both Statement I and Statement II are false
(B)Both Statement I and Statement II are true
(C)Statement I is true but Statement II is false
(D)Statement I is false but Statement II is true
Q7·ChemistryIntegerJEE Main 2025
The possible number of stereoisomers for 5-phenylpent-4-en-2-ol is __________.
Q8·ChemistrySingle correctJEE Main 2025
How many different stereoisomers are possible for the molecule hex-3-en-2-ol, CH₃–CH(OH)–CH=CH–CH₂–CH₃ ?
(A)3
(B)1
(C)2
(D)4
Q9·ChemistrySingle correctJEE Main 2024
Total number of stereoisomers possible for the structure shown in the figure is:
(A)8
(B)2
(C)4
(D)3
Q10·ChemistryNumericalJEE Main 2024
The number of optical isomers in the following compound is ___ (structure shown)
Q11·ChemistryNumericalJEE Main 2024
Total number of optically active compounds from the following is _______ .
Q12·ChemistrySingle correctJEE Main 2024
Which of the following (shown in the figure) is a metamer of the given compound (X)?
(A)(1)
(B)(2)
(C)(3)
(D)(4)
Q13·ChemistrySingle correctJEE Main 2024
The incorrect statement regarding the geometrical isomers of 2-butene is:
(A)cis-2-butene and trans-2-butene are not interconvertible at room temperature.
(B)cis-2-butene has less dipole moment than trans-2-butene.
(C)trans-2-butene is more stable than cis-2-butene.
(D)cis-2-butene and trans-2-butene are stereoisomers.
Q14·ChemistrySingle correctJEE Main 2024
Match List-I (pair of compounds) with List-II (type of isomerism). Choose the correct answer from the options given below:
List-I (Pair of Compounds)
List-II (Isomerism)
A.n-Propanol and isopropanol
I.Metamerism
B.Methoxypropane and ethoxyethane
II.Chain isomerism
C.Propanone and propanal
III.Position isomerism
D.Neopentane and isopentane
IV.Functional isomerism
(A)(A)-(II), (B)-(I), (C)-(IV), (D)-(III)
(B)(A)-(III), (B)-(I), (C)-(II), (D)-(IV)
(C)(A)-(I), (B)-(III), (C)-(IV), (D)-(II)
(D)(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Q15·ChemistryNumericalJEE Main 2024
The number of different chain isomers for C7H16 is ___
Q16·ChemistryNumericalJEE Main 2024
Number of optical isomers possible for 2-chlorobutane is ___
Q17·ChemistryNumericalJEE Main 2024
Number of geometrical isomers possible for the given structure is/are ______.
Q18·ChemistrySingle correctJEE Main 2024
Which one of the following will show geometrical isomerism?
(A)(1)
(B)(2)
(C)(3)
(D)(4)
Q19·ChemistrySingle correctJEE Main 2024
The incorrect statement regarding conformations of ethane is : (1) the infinite number of conformations of ethane. (2) the dihedral angle in staggered conformation is 60∘. (3) eclipsed conformation is the most stable conformation. (4) the conformations of ethane are inter-convertible to one-another.
(A)the infinite number of conformations of ethane
(B)the dihedral angle in staggered conformation is 60∘
(C)eclipsed conformation is the most stable conformation
(D)the conformations of ethane are inter-convertible to one-another
Q20·ChemistryNumericalJEE Main 2024
Total number of compounds from the following with Chiral carbon atoms is __________.
Q21·ChemistrySingle correctJEE Main 2024
Highest enol content will be shown by:
(A)(1)
(B)(2)
(C)(3)
(D)(4)
Q22·ChemistryNumericalJEE Main 2023
The total number of chiral compound/s from the compounds shown in the figure is _______ .
Q23·ChemistrySingle correctJEE Main 2023
Match List I (Isomeric pairs) with List II (Type of isomers) and choose the correct answer from the options given below.
LIST I (Isomeric pairs)
LIST II (Type of isomers)
A.Propanamine and N-Methylethanamine
I.Metamers
B.Hexan-2-one and Hexan-3-one
II.Positional isomers
C.Ethanamide and Hydroxyethanimine
III.Functional isomers
D.o-nitrophenol and p-nitrophenol
IV.Tautomers
(A)A-II, B-III, C-I, D-IV
(B)A-III, B-I, C-IV, D-II
(C)A-III, B-IV, C-I, D-II
(D)A-IV, B-III, C-I, D-II
Q24·ChemistrySingle correctJEE Main 2023
The isomeric deuterated bromide with molecular formula C4H8DBr having two chiral carbon atoms is
(A)2-Bromo-2-deuterobutane
(B)2-Bromo-1-deuterobutane
(C)2-Bromo-1-deutero-2-methylpropane
(D)2-Bromo-3-deuterobutane
Q25·ChemistrySingle correctJEE Main 2023
Which of the following conformations (shown as Newman projections in the figure) will be the most stable?
(A)(1)
(B)(2)
(C)(3)
(D)(4)
Q26·ChemistryIntegerJEE Advanced 2022
The total number of chiral molecules formed from one molecule of P on complete ozonolysis (O3,Zn/H2O) is____.
Q27·ChemistryNumericalJEE Main 2022
Optical activity of an enantiomeric mixture is +12.6° and the specific rotation of (+) isomer is +30°. The optical purity is____%
Q28·ChemistryNumericalJEE Main 2022
Observe structures of the following compounds
The total number of structures/compounds which possess asymmetric carbon atoms is _______ .
Q29·ChemistryNumericalJEE Main 2022
Total number of possible stereoisomers of dimethyl cyclopentane is ___________
Q30·ChemistrySingle correctJEE Advanced 2021
Among the following, the conformation that corresponds to the most stable conformation of meso–butane–2,3–diol is –
(A)(A)
(B)(B)
(C)(C)
(D)(D)
Q31·ChemistryIntegerJEE Advanced 2021
The maximum number of possible isomers (including stereoisomers) which may be formed on mono-bromination of 1-methylcyclohex-1-ene using Br2 and UV light is ____
Q32·ChemistrySingle correctJEE Main 2021
The stereoisomers that are formed by electrophilic addition of bromine to trans-but-2-ene is/are :
(A)2 enantiomers and 2 mesomers
(B)2 identical mesomers
(C)2 enantiomers
(D)1 racemic and 2 enantiomers
Q33·ChemistrySingle correctJEE Main 2021
Arrange the following conformational isomers of n-butane in order of their increasing potential energy :
(A)II < III < IV < I
(B)I < IV < III < II
(C)II < IV < III < I
(D)I < III < IV < II
Q34·ChemistrySingle correctJEE Main 2021
The number of stereoisomers possible for 1,2-dimethyl cyclopropane is :
(A)One
(B)Four
(C)Two
(D)Three
Q35·ChemistrySingle correctJEE Main 2021
Staggered and eclipsed conformers of ethane are:
(A)Mirror images
(B)Polymers
(C)Enantiomers
(D)Rotamers
Q36·ChemistrySingle correctJEE Main 2021
Which one of the following pairs of isomers is an example of metamerism?
(A)(A)
(B)(B)
(C)(C)
(D)(D)
Q37·ChemistrySingle correctJEE Main 2021
Compound with molecular formula C3H6O can show :
(A)Positional isomerism
(B)Both positional isomerism and metamerism
(C)Metamerism
(D)Functional group isomerism
Q38·ChemistrySingle correctJEE Advanced 2020
The Fischer projection of D-erythrose is shown below.
D-Erythrose and its isomers are listed as P, Q, R, and S in Column-I. Choose the correct relationship of P, Q, R, and S with D-erythrose from Column II.
Column-I
Column-II
P.see figure
1.Diastereomer
Q.see figure
2.Identical
R.see figure
3.Enantiomer
S.see figure
(A)P → 2, Q → 3, R → 2, S → 2
(B)P → 3, Q → 1, R → 1, S → 2
(C)P → 2, Q → 1, R → 1, S → 3
(D)P → 2, Q → 3, R → 3, S → 1
Q39·ChemistrySingle correctJEE Advanced 2020
Newman projections P, Q, R and S are shown below :
Which one of the following options represents identical molecules ?
(A)P and Q
(B)Q and S
(C)Q and R
(D)R and S
Q40·ChemistryIntegerJEE Advanced 2020
An organic compound (C8H10O2) rotates plane-polarized light. It produces pink color with neutral FeCl3 solution. What is the total number of all the possible isomers for this compound?
Q41·ChemistrySingle correctJEE Main 2020
Which of the following compounds shows geometrical isomerism?
(A)2 – methylpent 2 – ene
(B)4 – methylpent 2 – ene
(C)4 – methylpent – 1 – ene
(D)2 – methylpent –1 – ene
Q42·ChemistrySingle correctJEE Main 2020
Among the following compounds, geometrical isomerism is exhibited by:
(A)(A)
(B)(B)
(C)(C)
(D)(D)
Q43·ChemistryNumericalJEE Main 2020
The number of chiral centres present in [B] is ___________.
Q44·ChemistrySingle correctJEE Main 2020
Which of the following compounds produces an optically inactive compound on hydrogenation?
(A)(A)
(B)(B)
(C)(C)
(D)(D)
Q45·ChemistrySingle correctJEE Main 2020
Which of the following reactions will not produce a racemic product?
(A)(A)
(B)(B)
(C)(C)
(D)(D)
Q46·ChemistryNumericalJEE Main 2020
The number of chiral carbons in chloramphenicol is
Q47·ChemistryNumericalJEE Advanced 2019
Total number of isomers, considering both structural and stereoisomers, of cyclic ethers with the molecular formula C4H8O is________
Q48·ChemistrySingle correctJEE Main 2019
In the following skew conformation of ethane, H'\u2013C\u2013C\u2013H" dihedral angle is :
(A)58°
(B)120°
(C)149°
(D)151°
Q49·ChemistrySingle correctJEE Main 2019
Which of these factors does not govern the stability of a conformation in acyclic compounds?
(A)Torsional strain
(B)Angle strain
(C)Steric interactions
(D)Electrostatic forces of interaction
Q50·ChemistryNumericalJEE Advanced 2018
For the given compound X, the total number of optically active stereoisomers is ____
This type of bond indicates that the configuration at the specific carbon and geometry of the double bond is fixed
This type of bond indicates that the configuration at the specific carbon and the geometry of the double bond is NOT fixed
Q51·ChemistryMultiple correctJEE Advanced 2017
The correct statement(s) for the following addition reactions is(are)
(A)(M and O) and (N and P) are two pairs of diastereomers
(B)Bromination proceeds through trans-addition in both the reactions
(C)O and P are identical molecules
(D)(M and O) and (N and P) are two pairs of enantiomers
Q52·ChemistryIntegerJEE Advanced 2016
In the following monobromination reaction, the number of possible chiral products is
Q53·ChemistryMultiple correctJEE Advanced 2015
Compound(s) that on hydrogenation produce(s) optically inactive compound(s) is (are)
(A)(A)
(B)(B)
(C)(C)
(D)(D)
Q54·ChemistryIntegerJEE Advanced 2015
The total number of stereoisomers that can exist for M is
Q55·ChemistryIntegerJEE Advanced 2014
The total number(s) of stable conformers with non-zero dipole moment for the following compound is(are)
Q56·ChemistrySingle correctJEE Advanced 2013
P and Q are isomers of dicarboxylic acid C4H4O4. Both decolorize Br2/H2O. On heating, P forms the cyclic anhydride.
Upon treatment with dilute alkaline KMnO4, P as well as Q could produce one or more than one from S, T and U.
Compounds formed from P and Q are, respectively
(A)Optically active S and optically active pair (T, U)
(B)Optically inactive S and optically inactive pair (T, U)
(C)Optically active pair (T, U) and optically active S
(D)Optically inactive pair (T, U) and optically inactive S
Isomerism — frequently asked
How many questions from Isomerism appear in JEE?
Isomerism has appeared in 51 of the last 186 JEE Main and JEE Advanced papers — about 27% of them — contributing 56 questions in total across those papers.
Is Isomerism an important chapter for JEE?
Judged by how often it is actually tested, it appears in roughly 27% of papers. Chapters above about 50% are effectively guaranteed to show up every session, so they repay thorough preparation; lower-frequency chapters are better treated as targeted revision.
Where do these Isomerism questions come from?
Every question is from an official JEE Main or JEE Advanced paper, transcribed from the original paper and tagged to this chapter. Answers follow the official answer key.
Practise Isomerism until it stops costing you marks.
Build a timed test from these 56 questions in one click. Jarvis marks it, names the specific misconception behind each wrong answer, and brings the ones you failed back at the right interval.