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NEET

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

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Haloalkanes and Haloarenes

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Q 1. Identify {tex} A {/tex} and predict the type of reaction

A

B

C

Explanation


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Q 2. Consider the reaction,
{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { CH } _ { 2 } \mathrm { Br } + \mathrm { NaCN } \rightarrow \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { CH } _ { 2 } \mathrm { CN }+ \mathrm { NaBr }{/tex}
This reaction will be the fastest in

A

ethanol

B

methanol

{tex} N , N ^ { \prime } {/tex} -dimethylformamide (DMF)

D

water

Explanation


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Q 3. Two possible stereo-structures of {tex} \mathrm { CH } _ { 3 } \mathrm { CHOHCOOH } , {/tex} which are optically active, are called

A

atropisomers

enantiomers

C

mesomers

D

diastereomers.

Explanation

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Q 4. The reaction of {tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } = \mathrm { CHCH } _ { 3 } {/tex} with {tex} \mathrm { HBr} {/tex} produces

A

{tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } _ { 2 } \mathrm { CH } _ { 2 } \mathrm { CH } _ { 2 } \mathrm { Br } {/tex}

B

D

Explanation

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Q 5. Which of the following compounds will undergo racemisation when solution of KOH hydrolyses?

A

(i) and (ii)

B

(ii) and (iv)

(iv) only

D

(i) and (iv)

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Q 6. Given:

I and II are

A

identical

a pair of conformers

C

a pair of geometrical isomers

D

a pair of optical isomers

Explanation


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Q 7. In the replacement reaction

The reaction will be most favourable if {tex} \mathrm M {/tex} happens to be

A

{tex} \mathrm { Na } {/tex}

B

{tex} \mathrm { K } {/tex}

{tex} \mathrm { Rb } {/tex}

D

{tex} \text { Li} {/tex}

Explanation


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Q 8. Consider the reactions.

The mechanisms of reactions (i) and (ii) are respectively

A

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

B

{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}

D

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

Explanation


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Q 9. The correct order of increasing reactivity of

C-X bond towards nucleophile in the following compounds is

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

B

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

C

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

D

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

Explanation


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Q 10. In the following reaction,
{tex}\mathrm{C_6H_5CH_2Br \xrightarrow [2.\ \mathrm{H_3O^+}]{1.\ \mathrm{Mg,\ Ether}}X}{/tex}, the product '{tex}\mathrm X{/tex}' is

A

{tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } _ { 2 } \mathrm { OCH } _ { 2 } \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } {/tex}

B

{tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } _ { 2 } \mathrm { OH } {/tex}

{tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } _ { 3 } {/tex}

D

{tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } _ { 2 } \mathrm { CH } _ { 2 } \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } {/tex}

Explanation

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Q 11. Which of the following reactions is an example of nucleophilic substitution reaction?

A

{tex} 2 \mathrm R X + 2 \mathrm { Na } \rightarrow \mathrm R - \mathrm R + 2 \mathrm { Na } \mathrm X {/tex}

B

{tex} \mathrm R \mathrm X + \mathrm { H } _ { 2 } \rightarrow \mathrm R \mathrm { H } + \mathrm { HX } {/tex}

C

{tex} \mathrm R \mathrm X + \mathrm { Mg } \rightarrow \mathrm R \mathrm { Mg } \mathrm X {/tex}

{tex} \mathrm R \mathrm X + \mathrm { KOH } \rightarrow \mathrm R \mathrm { OH } + \mathrm { KX } {/tex}

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Q 12. If there is no rotation of plane polarised light by a compound in a specific solvent, though to be chiral, it may mean that

the compound is certainly meso

B

there is no compound in the solvent

C

the compound may be a racemic mixture

D

the compound is certainly a chiral

Explanation

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Q 13. Which of the following is least reactive in a nucleophilic substitution reaction?

A

{tex} \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { C } - \mathrm { Cl } {/tex}

{tex} \mathrm { CH } _ { 2 } = \mathrm { CHCl } {/tex}

C

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

D

{tex} \mathrm { CH } _ { 2 } = \mathrm { CHCH } _ { 2 } \mathrm { Cl } {/tex}

Explanation



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Q 14. Which of the following pairs of compounds are enantiomers?

B

C

D

Explanation