JEE Main > Haloalkanes and Haloarenes

Explore popular questions from Haloalkanes and Haloarenes for JEE Main. This collection covers Haloalkanes and Haloarenes previous year JEE Main questions hand picked by popular teachers.


Q 1.    

Correct4

Incorrect-1

Consider the reaction:

The mechanisms of reaction (i) and (ii) are, respectively:

A

{tex} \mathrm { S } _ { \mathrm { N } } 2 {/tex} and {tex} \mathrm { S } _ { \mathrm { N } } 1 {/tex}

B

{tex} \mathrm { S } _ { \mathrm { N } } 1 {/tex} and {tex} \mathrm { S } _ { \mathrm { N } } 2 {/tex}

C

{tex} \mathrm { S } _ { \mathrm { N } } 1 {/tex} and {tex} \mathrm { S } _ { \mathrm { N } } 1 {/tex}

{tex} \mathrm { S } _ { \mathrm { N } } 2 {/tex} and {tex} \mathrm { S } _ { \mathrm { N } } 2 {/tex}

Explanation

Q 2.    

Correct4

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{tex} 2,2 {/tex}-Dichloropentane can best be synthesised by:

A

B

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { CH } _ { 2 } \mathrm { C } = \mathrm { CH } \stackrel { \mathrm { H } _ { 2 } } { \longrightarrow } [ \mathrm { A } ] \stackrel { \mathrm { Cl } _ { 2 } } { \longrightarrow } {/tex}

D

Explanation

Q 3.    

Correct4

Incorrect-1

B

C

D

Explanation

Q 4.    

Correct4

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The end product (C) of given sequence of reaction is:

A

{tex} \mathrm { CH } _ { 2 } \mathrm { BrCOOAg } {/tex}

B

C

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { Br } {/tex}

{tex} \mathrm { CH } _ { 3 } \mathrm { Br } {/tex}

Explanation

Q 5.    

Correct4

Incorrect-1

B

C

D

Explanation

Q 6.    

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Which of the following is true about given graph {tex} \mathrm { A } {/tex} and {tex} \mathrm { B } ? {/tex}

{tex} \mathrm { A } \rightarrow \mathrm { S } _ { \mathrm { N } } 1 \mathrm { B } \rightarrow \mathrm { S } _ { \mathrm { N } } 2 {/tex}

B

A {tex}\mathrm{\rightarrow S_N2, B \rightarrow S_N1 }{/tex}

C

{tex} A {/tex} and {tex} B \rightarrow E _ { 1 } {/tex}

D

{tex} A {/tex} and {tex} B \rightarrow E _ { 2 } {/tex}

Explanation

Q 7.    

Correct4

Incorrect-1

Ethyl alcohol reacts at faster rate with HI than with HCl in forming the corresponding ethyl halides under identical conditions mainly because:

A

HI, being a stronger acid, protonates ethyl alcoho at oxygen much better and helps substitution

B

the bond length in HI is much shorter than that in {tex} \mathrm { HCl } {/tex}

C

{tex}\mathrm{I^-}{/tex} derived from HI is a much better leaving group

{tex}\mathrm{I^-}{/tex} derived from HI is a much better nucleophile than {tex} \mathrm { CI } ^ { - } {/tex}

Explanation

Q 8.    

Correct4

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Identify the correct reaction to synthesise the following compound from cyclopentane.

A

B

D

None of these

Explanation

Q 9.    

Correct4

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Which of the following reactions will result in the formation of a chiral centre in the product?

A

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } = \mathrm { CH } _ { 2 } + \mathrm { HBr } \longrightarrow {/tex}

B

{tex} \mathrm { CH } _ { 2 } = \mathrm { CH } _ { 2 } + \mathrm { HOBr } \longrightarrow {/tex}

C

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { CH } = \mathrm { CH } _ { 2 } + \mathrm { HBr } \longrightarrow {/tex}

Explanation

Q 10.    

Correct4

Incorrect-1

In the presence of dibenzoyl peroxide, addition of HBr to 1-butene produces

A

2-bromobutane

1-bromobutane

C

{tex} ( \pm ) - 2 {/tex}-bromobutane

D

1-bromobutene

Explanation

Q 11.    

Correct4

Incorrect-1

The reaction of {tex} ( S ) - 2 {/tex} -bromobutane with {tex} \mathrm { OH } ^ { - } {/tex} to produce (R)-butan-2-ol will be

A

first order in 2-bromobutane only

B

first order in {tex} \mathrm { OH } ^ { - } {/tex} only

first order in 2-bromobutane and first order in {tex} \mathrm { OH } ^ { - } {/tex}

D

second order in {tex} \mathrm { OH } ^ { - } {/tex}

Explanation

Q 12.    

Correct4

Incorrect-1

The correct order of increasing reactivity of the sub- strates {tex} ( \mathrm { I } ) , {/tex} (II), {tex} ( \mathrm { III } ) , {/tex} and {tex} ( \mathrm { IV } ) {/tex} below, towards {tex} \mathrm { S } _ { \mathrm { N } } 1 {/tex} reaction with a given nucleophile is:

B

{tex} \mathrm { II } < \mathrm { I } < \mathrm { III } < \mathrm { IV } {/tex}

C

{tex} \mathrm { IV } < \mathrm { II } < \mathrm { I } < \mathrm { III } {/tex}

D

{tex} \mathrm { III } < \mathrm { IV } < \mathrm { II } < \mathrm { I } {/tex}

Explanation

Q 13.    

Correct4

Incorrect-1

Among the bromides I-III given below, the order of reactivity of {tex} \mathrm { S } _ { \mathrm { N } } {/tex} 1 reaction is:

III {tex} > 1 > 1 {/tex}

B

III {tex} > {/tex} II {tex} > 1 {/tex}

C

{tex} \mathrm { II } > \mathrm { III } > 1 {/tex}

D

{tex} \mathrm { II } > \mathrm { I } > \mathrm { III } {/tex}

Explanation

Q 14.    

Correct4

Incorrect-1

The {tex} S _ { N } ^ { 2 } {/tex} reaction of 1-chloro-3-methylbutane with sodium methoxide is relative slow, but can be accelerated by the addition of a small amount of NaI. How this catalysis is best explained?

A

The sodium cation helps pull off the chloride anion

B

The iodide anion activates the methoxide nucleophile

{tex} S _ { N } ^ { 2 } {/tex} reaction of iodide ion converts the alkyl chloride to the more reactive alkyl iodide

D

The Nal changes the mechanism to {tex} \mathrm { S } _ { \mathrm { N } } ^ { 1 } {/tex}

Explanation

Q 15.    

Correct4

Incorrect-1


The major product in this reaction is:

A

B

D

Explanation

Q 16.    

Correct4

Incorrect-1

Isopropylidene chloride is hydrolysed with aqueous NaOH. The product formed is:

A

1-propanal

B

propanal

C

2-propanal

propanone

Explanation

Q 17.    

Correct4

Incorrect-1


The given reaction undergoes

unimolecular substitution predominantly.

B

unimolecular elimination predominantly.

C

bimolecular substitution predominantly.

D

bimolecular elimination predominantly.

Explanation

Q 18.    

Correct4

Incorrect-1


Major product

{tex} \mathrm { CH } _ { 3 } - \mathrm { CH } = \mathrm { CH } _ { 2 } {/tex} by {tex} \mathrm { E } _ { 2 } {/tex} pathway

B

C

{tex} \mathrm { CH } _ { 3 } - \mathrm { CH } = \mathrm { CH } _ { 2 } {/tex} by El pathway

D

Explanation

Q 19.    

Correct4

Incorrect-1


Select the major product and path of mechanism of given reaction

A

B

D

Explanation

Q 20.    

Correct4

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What would be major product of given reaction?

B

C

D

Explanation

Q 21.    

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The product formed in the reaction is:

A

C

D

Explanation

Q 22.    

Correct4

Incorrect-1

The product formed in the reaction is:

A

C

D

Explanation

Q 23.    

Correct4

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{tex} \mathrm { CHCl } _ { 3 } \stackrel { \mathrm { OH } ^ { - } / \mathrm { H } _ { 2 } \mathrm { O } } { \longrightarrow } \mathrm { A } , \mathrm { A } {/tex} is

A

{tex} \mathrm{CO^{2-}_3} {/tex}

B

D

{tex} \mathrm { C } _ { 2 } \mathrm { O } _ { 4 } ^ { 2 - } {/tex}

Explanation

Q 24.    

Correct4

Incorrect-1

Identify {tex} ( \mathrm { X } ): {/tex}

{tex} \mathrm { F } _ { 2 } \mathrm { C } = \mathrm { CF } _ { 2 } {/tex}

B

{tex} \mathrm { ClFC } = \mathrm { CFCl } {/tex}

C

{tex} \mathrm { F } _ { 2 } \mathrm { C } = \mathrm { CFCl } {/tex}

D

{tex} \mathrm { F } _ { 2 } \mathrm { C } = \mathrm { CCl } _ { 2 } {/tex}

Explanation

Q 25.    

Correct4

Incorrect-1

A

{tex} 3 : 4 {/tex}

{tex} 2 : 3 {/tex}

C

{tex} 3 : 2 {/tex}

D

{tex} 4 : 3 {/tex}

Explanation