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JEE Advanced > Hydrocarbons

Explore popular questions from Hydrocarbons for JEE Advanced. This collection covers Hydrocarbons previous year JEE Advanced questions hand picked by experienced teachers.

Q 1.

Correct4

Incorrect-1

Marsh gas mainly contains

A

{tex} \mathrm { C } _ { 2 } \mathrm { H } _ { 2 } {/tex}

{tex} \mathrm { CH } _ { 4 } {/tex}

C

{tex} \mathrm { H } _ { 2 } \mathrm { S } {/tex}

D

{tex} \mathrm { CO } {/tex}

Q 2.

Correct4

Incorrect-1

The compound with the highest boiling point is

{tex} n {/tex} -hexane

B

{tex} n - {/tex} pentane

C

{tex} 2,2 {/tex} -dimethylpropane

D

{tex}2{/tex} - methylbutane

Explanation

Q 3.

Correct4

Incorrect-1

The reaction conditions leading to the best yield of {tex} \mathrm { C } _ { 2 } \mathrm { H } _ { 5 } \mathrm { Cl } {/tex} are

{tex} \mathrm { C } _ { 2 } \mathrm { H } _ { 6 } ( \mathrm { excess } ) + \mathrm { Cl } _ { 2 } \stackrel { \mathrm { uvlight } } { \longrightarrow } {/tex}

B

{tex} \mathrm { C } _ { 2 } \mathrm { H } _ { 6 } + \mathrm { Cl } _ { 2 }\xrightarrow[\mathrm{room temperature}]{\mathrm{dark}}{/tex}

C

{tex} \mathrm { C } _ { 2 } \mathrm { H } _ { 6 } + \mathrm { Cl } _ { 2 } ( \text { excess } ) \stackrel { \text { uv light } } { \longrightarrow } {/tex}

D

{tex} \mathrm { C } _ { 2 } \mathrm { H } _ { 6 } + \mathrm { Cl } _ { 2 } \stackrel { \text { uv light } } { \longrightarrow } {/tex}

Explanation

Q 4.

Correct4

Incorrect-1

The highest boiling point is expected for

A

isooctane

{tex} n {/tex} -octane

C

{tex} 2,2,3,3 {/tex} -tetramethylbutane

D

{tex} n {/tex} -butane

Explanation

Q 5.

Correct4

Incorrect-1

Which of the following will have least hindered rotation about carbon-carbon bond?

Ethane

B

Ethylene

C

Acetylene

D

hexachloroethane

Explanation

Q 6.

Correct4

Incorrect-1

When cyclohexane is poured on water, it floats, because:

A

cyclohexane is in 'boat' form

B

cyclohexane is in 'chair' form

C

cyclohexane is in 'crown' form

cyclohexane is less dense than water.

Q 7.

Correct4

Incorrect-1

Benzyl chlorice {tex} \left( \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } _ { 2 } \mathrm { Cl } \right) {/tex} can be prepared from toluene by chlorination with

A

{tex} \mathrm { SO } _ { 2 } \mathrm { Cl } _ { 2 } {/tex}

B

{tex} \mathrm { SOCl } _ { 2 } {/tex}

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

D

{tex} \mathrm { NaOCl } {/tex}

Q 8.

Correct4

Incorrect-1

Consider the follwing reaction:
Identify the structure of the major product {tex}\mathrm{'X'}{/tex}

A

C

D

Explanation

Q 9.

Correct4

Incorrect-1

In the given conformation,
{tex} \mathrm { C } _ { 2 } {/tex} is rotated about {tex} \mathrm { C } _ { 2 } - \mathrm { C } _ { 3 } {/tex} bond clockwise by an of angle {tex} 120 ^ { \circ } . {/tex} The obtained conformation is

A

anti conformation

gauche conformation

C

partially eclipsed conformation

D

fully eclipsed conformation

Explanation

Q 10.

Correct4

Incorrect-1

In the reaction {tex} \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CHCH } _ { 2 } \mathrm { CH } _ { 3 } \xrightarrow [{ \mathrm{hv} }] {\mathrm{ Cl } _ { 3 } }{/tex} isomers of {tex} \mathrm { C } _ { 5 } \mathrm { H } _ { 11 } \mathrm { Cl } \xrightarrow [{ \text { distillation } }] { \text { Fractional } }n {/tex} distilled products. The values of {tex} N {/tex} and {tex} n {/tex} respectively are

A

{tex} 6,6 {/tex}

{tex} 6,4 {/tex}

C

{tex} 4,6 {/tex}

D

{tex} 4,4 {/tex}

Explanation


Q 11.

Correct4

Incorrect-1

Isomers of hexane, based on their branching, can be divided into three distinct classes as shown in the figure.

The correct order of their boiling points is

A

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

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

C

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

D

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

Explanation

Q 12.

Correct4

Incorrect-1

Baeyer's reagent is

alkaline potassium perman ganate solution

B

acidified potassium permangnate solution

C

neutral potassium permangnate solution

D

aqueous bromine solution

Explanation

Q 13.

Correct4

Incorrect-1

Anti-Markovnikov addition of {tex}\mathrm{HBr}{/tex} is not observed in

A

propene

B

butene

{tex}2{/tex}-butene

D

{tex}2{/tex}-pentene

Explanation

Q 14.

Correct4

Incorrect-1

Of the following compounds, which will have a zero dipole moment?

A

{tex} 1,1 {/tex}-dichlorothylene

B

cis-{tex}1,2{/tex}-dichloroethylene

trans-{tex}1,2{/tex}-dichloroethylene

D

none of these compounds

Explanation

Q 15.

Correct4

Incorrect-1

{tex} n {/tex} - Propyl bromide on treating with ethanolic potassium hydroxide produces

A

propane

propene

C

propyne

D

propanol

Explanation

Q 16.

Correct4

Incorrect-1

In {tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { OH } , {/tex} the bond that undergoes heterolytic cleavage most readily is

A

{tex} \mathrm { C } - \mathrm { C } {/tex}

B

{tex} \mathrm { C } - \mathrm { H } {/tex}

C

{tex} \mathrm { C } - \mathrm { O } {/tex}

{tex} \mathrm { O } - \mathrm { H } {/tex}

Explanation

Q 17.

Correct4

Incorrect-1

{tex}1{/tex}-Chlorobutane on reaction with alcoholic potash gives

{tex}1{/tex}-butene

B

{tex} \mathrm { C } - \mathrm { H } {/tex}

C

{tex}2{/tex}-butene

D

{tex}2{/tex}-butanol

Explanation

Q 18.

Correct4

Incorrect-1

Which one of the following has the smallest heat of hydrogenation per mole?

A

{tex}1{/tex} -Butene

B

trans- {tex}2{/tex} - Butene

C

cis -{tex}2{/tex}-Butene

{tex} 1,3 {/tex} -Butadiene

Explanation

Q 19.

Correct4

Incorrect-1

During debromoniation of meso-dibromobutane, the major compound formed is

A

{tex} n {/tex} -butane

B

{tex}1{/tex}-butene

C

cis- {tex}2{/tex} -butene

trans {tex} - 2 {/tex} -butene.

Explanation

Q 20.

Correct4

Incorrect-1

The intermediate during the addition of {tex} \mathrm { HCl } {/tex} to propene in the presence of peroxide is

A

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

{tex} \mathrm { CH } _ { 3 } \mathrm {\stackrel{+} CHCH } _ { 3 } {/tex}

C

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

D

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm {\stackrel{+}CH } _ { 2 } {/tex}

Explanation

Q 21.

Correct4

Incorrect-1

The reaction of with {tex}\mathrm{HBr}{/tex} gives

A

C

D

Explanation



Q 22.

Correct4

Incorrect-1

Which one of the following alkenes will react fastest with {tex} \mathrm { H } _ { 2 } {/tex} under catalvtic hydrogenation condition?

B

C

D

Explanation

Q 23.

Correct4

Incorrect-1

The reaction of propene with {tex}\mathrm{HOCl}{/tex} proceeds via the addition of

A

{tex} \mathrm { H } ^ { + } {/tex} in the first step

{tex} \mathrm { Cl } ^ { + } {/tex} in the first step

C

{tex} \mathrm { OH } ^ { - } {/tex} in the first step

D

{tex} \mathrm { Cl } ^ { + } {/tex} and {tex} \mathrm { OH } ^ { - } {/tex} in a single step

Q 24.

Correct4

Incorrect-1

In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti-Markovnikov addition to alkenes because

A

both are highly ionic

B

one is oxidising and the other is reducing

one of the steps is endothermic in both the cases

D

all the steps are exothermic in both the cases

Q 25.

Correct4

Incorrect-1

When propyne is treated with aqueous {tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } {/tex} in the presence of {tex} \mathrm { HgSO } _ { 4 } {/tex}, the major product is

A

propanol

B

propyl hydrogen sulphate

acetone

D

propanal

Explanation