Reaction Mechanism — JEE Previous Year Questions

Every Reaction Mechanism question asked in JEE Main and JEE Advanced across the last 186 papers — 29 questions, each with its correct answer. Free to read, no account needed.

Questions

Papers it appeared in

29/186

Appearance rate

16%

All 29 Reaction Mechanism questions

Most recent papers first.

Q1·ChemistrySingle correctJEE Main 2026

The major product of which of the following reaction is not obtained by rearrangement reaction?

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q2·ChemistrySingle correctJEE Main 2026

Match the LIST-I (Reaction) with LIST-II (Mechanism). Choose the correct answer from the options given below:

List-I (Reaction)	List-II (Mechanism)
A.Williamson Synthesis	I.Electrophilic addition
B.Friedel Craft Reaction	II.Free radical substitution
C.Bromination of vinyl benzene	III.Nucleophilic substitution
D.Chlorination of toluene in light	IV.Electrophilic substitution

(A)A-III, B-I, C-II, D-IV
(B)A-III, B-IV, C-II, D-I
(C)A-III, B-IV, C-I, D-II
(D)A-I, B-III, C-IV, D-II

Q3·ChemistrySingle correctJEE Main 2025

Match the LIST-I with LIST-II. Choose the correct answer from the options given below:

LIST-I	LIST-II
A.Carbocation	I.Species that can supply a pair of electrons.
B.C-Free radical	II.Species that can receive a pair of electrons.
C.Nucleophile	III. $sp^2$ hybridized carbon with empty p-orbital.
D.Electrophile	IV. $sp^2/sp^3$ hybridized carbon with one unpaired electron.

(A)A-IV, B-II, C-III, D-I
(B)A-II, B-III, C-I, D-IV
(C)A-III, B-IV, C-II, D-I
(D)A-III, B-IV, C-I, D-II

Q4·ChemistryIntegerJEE Main 2025

Identify the structure of the final product (D) in the following sequence of reactions:

Ph{-}CO{-}CH_3 \xrightarrow{PCl_5,\ \Delta} A \xrightarrow{3\ eq.\ NaNH_2/NH_3} B \xrightarrow{Acidify} C \xrightarrow{1.\ B_2H_6;\ 2.\ H_2O_2/OH^-} D

Total number of

sp^2

hybridised carbon atoms in product D is __________.

Q5·ChemistrySingle correctJEE Main 2025

Total number of nucleophiles from the following is: NH

_3

, PhSH, (H

_3

_2

S, H

_2

C=CH

_2

^-

OH, H

_3

^+

, (CH

_3

)

_2

CO, (CH

_3

)

_2

C=NCH

_3

(A)5
(B)4
(C)7
(D)6

Q6·ChemistrySingle correctJEE Main 2024

Ionic reactions with organic compounds proceed through: (A) Homolytic bond cleavage (B) Heterolytic bond cleavage (C) Free radical formation (D) Primary free radical (E) Secondary free radical. Choose the correct answer from the options given below:

(A)(A) only
(B)(C) only
(C)(B) only
(D)(D) and (E) only

Q7·ChemistrySingle correctJEE Main 2024

A species having carbon with sextet of electrons and can act as electrophile is called

(A)carbon free radical
(B)carbanion
(C)carbocation
(D)pentavalent carbon

Q8·ChemistrySingle correctJEE Main 2023

The major product for the following reaction is:

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q9·ChemistrySingle correctJEE Main 2023

Correct statements for the given reaction 'A'

\xrightarrow{OH^-,\ 2eq}

'B' (where 'A' is the structure shown) are: A. Compound 'B' is aromatic. B. The completion of above reaction is very slow. C. 'A' shows tautomerism. D. The bond lengths C-C in compound B are found to be same. Choose the correct answer from the options given below:

(A)A, B and D only
(B)A, B and C only
(C)B, C and D only
(D)A, C and D only

Q10·ChemistrySingle correctJEE Main 2023

In the following reaction, 'B' is

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q11·ChemistryNumericalJEE Main 2023

A trisubstituted compound 'A', C

_{10}

_{12}

_2

gives neutral FeCl

_3

test positive. Treatment of compound 'A' with NaOH and CH

_3

Br gives C

_{11}

_{14}

_2

, with hydroiodic acid gives methyl iodide and with hot conc. NaOH gives a compound B, C

_{10}

_{12}

_2

. Compound 'A' also decolourises alkaline KMnO

_4

. The number of

\pi

bond/s present in the compound 'A' is

Q12·ChemistrySingle correctJEE Main 2023

In the following given reaction, 'A' is:

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q13·ChemistrySingle correctJEE Main 2022

(C_{7}H_{5}O_{2})_{2} \xrightarrow{h\nu} [X] + 2\dot{C}_{6}H_{5} + 2CO_{2}

Consider the above reaction and identify the intermediate 'X'

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q14·ChemistrySingle correctJEE Main 2022

The correct order of nucleophilicity is

(A) $F^- > OH^-$
(B) $H_2\overset{\cdot\cdot}{\underset{\cdot\cdot}{O}} > OH^-$
(C) $R\overset{\cdot\cdot}{\underset{\cdot\cdot}{O}}H > RO^-$
(D) $NH_2^- > NH_3$

Q15·ChemistryNumericalJEE Main 2022

Number of electrophilic centre in the given compound is ____

Q16·ChemistrySingle correctJEE Main 2021

Experimentally reducing a functional group cannot be done by which one of the following reagents ?

(A)Pt-C/H $_{2}$
(B)Na/H $_{2}$
(C)Pd-C/H $_{2}$
(D)Zn/H $_{2}$ O

Q17·ChemistryNumericalJEE Advanced 2020

In the following reaction, compound Q is obtained from compound P via an ionic intermediate What is the degree of unsaturation of Q ?

Q18·ChemistrySingle correctJEE Main 2020

The major products of the following reaction are:

CH_3-CH(CH_3)-CH(OSO_2CH_3)-CH_3

\xrightarrow{(i)\ KO^tBu/\Delta\quad (ii)\ O_3/H_2O_2}

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q19·ChemistrySingle correctJEE Main 2020

The mechanism of S

_N

1 reaction is given as: A student writes general characteristics based on the given mechanism as: (a) The reaction is favoured by weak nucleophiles. (b) R

^\oplus

would be easily formed if the substituents are bulky. (c) The reaction is accompanied by racemization. (d) The reaction is favoured by non-polar solvents. Which observations are correct?

(A)(b) and (d)
(B)(a), (b) and (c)
(C)(a) and (c)
(D)(a) and (b)

Q20·ChemistrySingle correctJEE Main 2020

The major products A and B in the following reactions are :

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q21·ChemistrySingle correctJEE Main 2020

Consider the following reactions, which of these reaction(s) will not produce Saytzeff product? (a) (CH

_3

)

_3

CCH(OH)CH

_3

\xrightarrow{cons.\ H_2SO_4}

(b) (CH

_3

)

_2

CHCH(Br)CH

_3

\xrightarrow{cons.\ KOH}

_3

)

_2

CHCH(Br)CH

_3

\xrightarrow{(CH_3)_3O^{\ominus}K^{\oplus}}

(d) (CH

_3

)

_2

C(OH)CH

_2

CHO

\xrightarrow{\Delta}

Which of these reaction(s) will not produce Saytzeff product?

(A)(b) and (d)
(B)(c) only
(C)(a), (c) and (d)
(D)(d) only

Q22·ChemistryMultiple correctJEE Advanced 2019

Choose the correct option(s) for the following set of reactions

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q23·ChemistrySingle correctJEE Main 2019

The increasing order of nucleophilicity of the following nucleophiles is : (a) CH

_3

_2^-

(b) H

_2

O (c) CH

_3

_3^-

(d)

\overline{\mathrm{O}}

(A)(b) < (c) < (a) < (d)
(B)(a) < (d) < (c) < (b)
(C)(d) < (a) < (c) < (b)
(D)(b) < (c) < (d) < (a)

Q24·ChemistrySingle correctJEE Main 2019

Which of the following potential energy (PE) diagrams represents the

S_N1

reaction?

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q25·ChemistrySingle correctJEE Main 2019

The major product obtained in the following conversion is:

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q26·ChemistrySingle correctJEE Main 2019

The major product of the following reaction is

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q27·ChemistryMultiple correctJEE Advanced 2018

In the following reaction sequence, the correct structure(s) of X is (are)

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q28·ChemistrySingle correctJEE Advanced 2018

LIST-I contains reactions and LIST-II contains major products. Match each reaction in LIST-I with one or more products in LIST-II and choose the correct option.

LIST-I	LIST-II
P.see figure	1.see figure
Q.see figure	2.see figure
R.see figure	3.see figure
S.see figure	4.see figure
	5.see figure

(A)P $\rightarrow$ 1,5; Q $\rightarrow$ 2; R $\rightarrow$ 3; S $\rightarrow$ 4
(B)P $\rightarrow$ 1,4; Q $\rightarrow$ 2; R $\rightarrow$ 4; S $\rightarrow$ 3
(C)P $\rightarrow$ 1,4; Q $\rightarrow$ 1,2; R $\rightarrow$ 3,4; S $\rightarrow$ 4
(D)P $\rightarrow$ 4,5; Q $\rightarrow$ 4; R $\rightarrow$ 4; S $\rightarrow$ 3,4

Q29·ChemistrySingle correctJEE Advanced 2014

Different possible thermal decomposition pathways for peroxyesters are shown below. Match each pathway from List I with an appropriate structure from List II and select the correct answer using the code given below the lists.

List-I	List-II
P.Pathway P	1.see figure
Q.Pathway Q	2.see figure
R.Pathway R	3.see figure
S.Pathway S	4.see figure

(A)P-1, Q-3, R-4, S-2
(B)P-2, Q-4, R-3, S-1
(C)P-4, Q-1, R-2, S-3
(D)P-3, Q-2, R-1, S-4

Reaction Mechanism — frequently asked

How many questions from Reaction Mechanism appear in JEE?

Reaction Mechanism has appeared in 29 of the last 186 JEE Main and JEE Advanced papers — about 16% of them — contributing 29 questions in total across those papers.

Is Reaction Mechanism an important chapter for JEE?

Judged by how often it is actually tested, it appears in roughly 16% 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 Reaction Mechanism 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.

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All 29 Reaction Mechanism questions

Most recent papers first.

Q1·ChemistrySingle correctJEE Main 2026

The major product of which of the following reaction is not obtained by rearrangement reaction?

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q2·ChemistrySingle correctJEE Main 2026

Match the LIST-I (Reaction) with LIST-II (Mechanism). Choose the correct answer from the options given below:

List-I (Reaction)	List-II (Mechanism)
A.Williamson Synthesis	I.Electrophilic addition
B.Friedel Craft Reaction	II.Free radical substitution
C.Bromination of vinyl benzene	III.Nucleophilic substitution
D.Chlorination of toluene in light	IV.Electrophilic substitution

(A)A-III, B-I, C-II, D-IV
(B)A-III, B-IV, C-II, D-I
(C)A-III, B-IV, C-I, D-II
(D)A-I, B-III, C-IV, D-II

Q3·ChemistrySingle correctJEE Main 2025

Match the LIST-I with LIST-II. Choose the correct answer from the options given below:

LIST-I	LIST-II
A.Carbocation	I.Species that can supply a pair of electrons.
B.C-Free radical	II.Species that can receive a pair of electrons.
C.Nucleophile	III. $sp^2$ hybridized carbon with empty p-orbital.
D.Electrophile	IV. $sp^2/sp^3$ hybridized carbon with one unpaired electron.

(A)A-IV, B-II, C-III, D-I
(B)A-II, B-III, C-I, D-IV
(C)A-III, B-IV, C-II, D-I
(D)A-III, B-IV, C-I, D-II

Q4·ChemistryIntegerJEE Main 2025

Identify the structure of the final product (D) in the following sequence of reactions:

Ph{-}CO{-}CH_3 \xrightarrow{PCl_5,\ \Delta} A \xrightarrow{3\ eq.\ NaNH_2/NH_3} B \xrightarrow{Acidify} C \xrightarrow{1.\ B_2H_6;\ 2.\ H_2O_2/OH^-} D

Total number of

sp^2

hybridised carbon atoms in product D is __________.

Q5·ChemistrySingle correctJEE Main 2025

Total number of nucleophiles from the following is: NH

_3

, PhSH, (H

_3

_2

S, H

_2

C=CH

_2

^-

OH, H

_3

^+

, (CH

_3

)

_2

CO, (CH

_3

)

_2

C=NCH

_3

(A)5
(B)4
(C)7
(D)6

Q6·ChemistrySingle correctJEE Main 2024

(A)(A) only
(B)(C) only
(C)(B) only
(D)(D) and (E) only

Q7·ChemistrySingle correctJEE Main 2024

A species having carbon with sextet of electrons and can act as electrophile is called

(A)carbon free radical
(B)carbanion
(C)carbocation
(D)pentavalent carbon

Q8·ChemistrySingle correctJEE Main 2023

The major product for the following reaction is:

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q9·ChemistrySingle correctJEE Main 2023

Correct statements for the given reaction 'A'

\xrightarrow{OH^-,\ 2eq}

(A)A, B and D only
(B)A, B and C only
(C)B, C and D only
(D)A, C and D only

Q10·ChemistrySingle correctJEE Main 2023

In the following reaction, 'B' is

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q11·ChemistryNumericalJEE Main 2023

A trisubstituted compound 'A', C

_{10}

_{12}

_2

gives neutral FeCl

_3

test positive. Treatment of compound 'A' with NaOH and CH

_3

Br gives C

_{11}

_{14}

_2

, with hydroiodic acid gives methyl iodide and with hot conc. NaOH gives a compound B, C

_{10}

_{12}

_2

. Compound 'A' also decolourises alkaline KMnO

_4

. The number of

\pi

bond/s present in the compound 'A' is

Q12·ChemistrySingle correctJEE Main 2023

In the following given reaction, 'A' is:

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q13·ChemistrySingle correctJEE Main 2022

(C_{7}H_{5}O_{2})_{2} \xrightarrow{h\nu} [X] + 2\dot{C}_{6}H_{5} + 2CO_{2}

Consider the above reaction and identify the intermediate 'X'

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q14·ChemistrySingle correctJEE Main 2022

The correct order of nucleophilicity is

(A) $F^- > OH^-$
(B) $H_2\overset{\cdot\cdot}{\underset{\cdot\cdot}{O}} > OH^-$
(C) $R\overset{\cdot\cdot}{\underset{\cdot\cdot}{O}}H > RO^-$
(D) $NH_2^- > NH_3$

Q15·ChemistryNumericalJEE Main 2022

Number of electrophilic centre in the given compound is ____

Q16·ChemistrySingle correctJEE Main 2021

Experimentally reducing a functional group cannot be done by which one of the following reagents ?

(A)Pt-C/H $_{2}$
(B)Na/H $_{2}$
(C)Pd-C/H $_{2}$
(D)Zn/H $_{2}$ O

Q17·ChemistryNumericalJEE Advanced 2020

In the following reaction, compound Q is obtained from compound P via an ionic intermediate What is the degree of unsaturation of Q ?

Q18·ChemistrySingle correctJEE Main 2020

The major products of the following reaction are:

CH_3-CH(CH_3)-CH(OSO_2CH_3)-CH_3

\xrightarrow{(i)\ KO^tBu/\Delta\quad (ii)\ O_3/H_2O_2}

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q19·ChemistrySingle correctJEE Main 2020

The mechanism of S

_N

1 reaction is given as: A student writes general characteristics based on the given mechanism as: (a) The reaction is favoured by weak nucleophiles. (b) R

^\oplus

would be easily formed if the substituents are bulky. (c) The reaction is accompanied by racemization. (d) The reaction is favoured by non-polar solvents. Which observations are correct?

(A)(b) and (d)
(B)(a), (b) and (c)
(C)(a) and (c)
(D)(a) and (b)

Q20·ChemistrySingle correctJEE Main 2020

The major products A and B in the following reactions are :

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q21·ChemistrySingle correctJEE Main 2020

Consider the following reactions, which of these reaction(s) will not produce Saytzeff product? (a) (CH

_3

)

_3

CCH(OH)CH

_3

\xrightarrow{cons.\ H_2SO_4}

(b) (CH

_3

)

_2

CHCH(Br)CH

_3

\xrightarrow{cons.\ KOH}

_3

)

_2

CHCH(Br)CH

_3

\xrightarrow{(CH_3)_3O^{\ominus}K^{\oplus}}

(d) (CH

_3

)

_2

C(OH)CH

_2

CHO

\xrightarrow{\Delta}

Which of these reaction(s) will not produce Saytzeff product?

(A)(b) and (d)
(B)(c) only
(C)(a), (c) and (d)
(D)(d) only

Q22·ChemistryMultiple correctJEE Advanced 2019

Choose the correct option(s) for the following set of reactions

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q23·ChemistrySingle correctJEE Main 2019

The increasing order of nucleophilicity of the following nucleophiles is : (a) CH

_3

_2^-

(b) H

_2

O (c) CH

_3

_3^-

(d)

\overline{\mathrm{O}}

(A)(b) < (c) < (a) < (d)
(B)(a) < (d) < (c) < (b)
(C)(d) < (a) < (c) < (b)
(D)(b) < (c) < (d) < (a)

Q24·ChemistrySingle correctJEE Main 2019

Which of the following potential energy (PE) diagrams represents the

S_N1

reaction?

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q25·ChemistrySingle correctJEE Main 2019

The major product obtained in the following conversion is:

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q26·ChemistrySingle correctJEE Main 2019

The major product of the following reaction is

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q27·ChemistryMultiple correctJEE Advanced 2018

In the following reaction sequence, the correct structure(s) of X is (are)

(A)(A)
(B)(B)
(C)(C)
(D)(D)

Q28·ChemistrySingle correctJEE Advanced 2018

LIST-I contains reactions and LIST-II contains major products. Match each reaction in LIST-I with one or more products in LIST-II and choose the correct option.

LIST-I	LIST-II
P.see figure	1.see figure
Q.see figure	2.see figure
R.see figure	3.see figure
S.see figure	4.see figure
	5.see figure

(A)P $\rightarrow$ 1,5; Q $\rightarrow$ 2; R $\rightarrow$ 3; S $\rightarrow$ 4
(B)P $\rightarrow$ 1,4; Q $\rightarrow$ 2; R $\rightarrow$ 4; S $\rightarrow$ 3
(C)P $\rightarrow$ 1,4; Q $\rightarrow$ 1,2; R $\rightarrow$ 3,4; S $\rightarrow$ 4
(D)P $\rightarrow$ 4,5; Q $\rightarrow$ 4; R $\rightarrow$ 4; S $\rightarrow$ 3,4

Q29·ChemistrySingle correctJEE Advanced 2014

List-I	List-II
P.Pathway P	1.see figure
Q.Pathway Q	2.see figure
R.Pathway R	3.see figure
S.Pathway S	4.see figure

(A)P-1, Q-3, R-4, S-2
(B)P-2, Q-4, R-3, S-1
(C)P-4, Q-1, R-2, S-3
(D)P-3, Q-2, R-1, S-4

Reaction Mechanism — frequently asked

How many questions from Reaction Mechanism appear in JEE?

Reaction Mechanism has appeared in 29 of the last 186 JEE Main and JEE Advanced papers — about 16% of them — contributing 29 questions in total across those papers.

Is Reaction Mechanism an important chapter for JEE?

Where do these Reaction Mechanism 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.