NEET

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

Biology

Hydrocarbons

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Q 1. Which one is the correct order of acidity?

{tex}\mathrm {CH\equiv CH>CH_3-C\equiv CH>CH_2=CH_2>CH_3-CH_3}{/tex}

B

{tex}\mathrm {CH\equiv CH>CH_2=CH_2 >CH_3-C\equiv CH>CH_3-CH_3}{/tex}

C

{tex}\mathrm {CH_3-CH_3>CH_2=CH_2>CH_3-C\equiv CH>CH\equiv CH }{/tex}

D

{tex}\mathrm {CH_2=CH_2>CH_3-CH=CH_2>CH_3-C\equiv CH>CH\equiv CH }{/tex}

Explanation

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Q 2. Predict the correct intermediate and product in the following reaction :

A

B

D

Explanation

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Q 3. With respect to the conformers of ethane, which of the following statements is true?

A

Bond angle changes but bond length remains same.

B

Both bond angle and bond length change.

Both bond angle and bond length remain same.

D

Bond angle remains same but bond length changes.

Explanation

In conformation bond angle and bond length remain same. There is only difference in spatial arrangement

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Q 4. Which of the following can be used as the halide component for Friedel-Crafts reaction?

A

Chlorobenzene

B

Bromobenzene

C

Chloroethene

Isopropyl chloride

Explanation

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Q 5. In which of the following molecules, all atoms are coplanar?

B

C

D

Explanation

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Q 6. In pyrrole the electron density is maximum on

A

2 and 3

B

3 and 4

C

2 and 4

2 and 5

Explanation

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Q 7. Which of the following compounds shall not produce propene by reaction with {tex}\mathrm{HBr}{/tex} followed by elimination or direct only elimination reaction?

A

B

D

Explanation

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Q 8. In the given reaction, the product P is

A

B

D

Explanation

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Q 9. The correct statement regarding the comparison of staggered and eclipsed conformations of ethane, is

A

the eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain

the staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has no torsional strain

C

the staggered conformation of ethane is less stable than eclipsed conformation, because staggered conformation has torsional strain

D

the eclipsed conformation of ethane is more stable than staggered conformation, because eclipsed conformation has no torsional strain.

Explanation

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Q 10. Consider the nitration of benzene using mixed conc.{tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } {/tex} and {tex} \mathrm { HNO } _ { 3 } {/tex}. If a large amount of {tex} \mathrm { KHSO } _ { 4 } {/tex} is added to the mixture, the rate of nitration will be

A

unchanged

B

doubled

C

faster

slower

Explanation

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Q 11. The pair of electrons in the given carbanion,{tex} \mathrm { CH } _ { 3 } \mathrm { C } \equiv \mathrm { C } ^ { - } , {/tex} is present in which of the following orbitals?

A

{tex} s p ^ { 2 } {/tex}

{tex} s p {/tex}

C

2{tex} p {/tex}

D

{tex} s p ^ { 3 } {/tex}

Explanation

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Q 12. In the reaction

{tex}X{/tex} and {tex}Y{/tex} are

A

{tex} X = 2-{/tex}Butyne, {tex} Y = 2{/tex}-Hexyne

B

{tex} X = 1 -{/tex}Butyne {tex} , Y = 2 {/tex}-Hexyne

{tex} X = 1-{/tex}Butyne, {tex} Y = 3{/tex}-Hexyne

D

{tex} X = 2-{/tex}Butyne {tex} , Y = 3{/tex}-Hexyne.

Explanation

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Q 13. In the reaction with {tex} \mathrm { HCl } {/tex} , an alkene reacts in accordance with the Markovnikov's rule to give a product 1-chloro-1 methylcyclohexane. The possible alkene is

A

B

{tex} ( A ) {/tex} and {tex} ( B ) {/tex}

D

Explanation

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Q 14. {tex} 2,3{/tex}-Dimethyl-2-butene can be prepared by heating which of the following compounds with a strong acid?

B

C

D

Explanation

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Q 15. A single compound of the structure,is obtainable from ozonolysis of which of the following cyclic compounds?

A

B

D

Explanation

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Q 16. Given:

The enthalpy of hydrogenation of these compounds will be in the order as

A

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

B

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

C

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

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

Explanation

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Q 17. What products are formed when the following compound is treated with {tex} \mathrm { Br } _ { 2 } {/tex} in the presence of {tex} \mathrm { FeBr } _ { 3 } ? {/tex}

B

C

D

None of the above

Explanation

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Q 18. Identify Z in the sequence of reactions :

{tex} \mathrm { CH_3-(CH } _ { 2 } ) _ { 3 } - \mathrm { O } - \mathrm { CH } _ { 2 } \mathrm { CH } _ { 3 } {/tex}

B

{tex} \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CH } - \mathrm { O } - \mathrm { CH } _ { 2 } \mathrm { CH } _ { 3 } {/tex}

C

{tex} \mathrm { CH } _ { 3 } \left( \mathrm { CH } _ { 2 } \right) _ { 4 } - \mathrm { O } - \mathrm { CH } _ { 3 }{/tex}

D

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - \mathrm { CH } \left( \mathrm { CH } _ { 3 } \right) - \mathrm { O } - \mathrm { CH } _ { 2 } \mathrm { CH } _ { 3 } {/tex}

Explanation

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Q 19. Which of the following organic compounds has same hybridization as its combustion product {tex} \left( \mathrm { CO } _ { 2 } \right) ? {/tex}

A

Ethane

Ethyne

C

Ethene

D

Ethanol

Explanation

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Q 20. Which of the following compounds will not undergo Friedal-Craft's reaction easily?

Nitrobenzene

B

Toluene

C

Cumene

D

Xylene

Explanation

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Q 21. Which of the following chemical system is non aromatic?

A

B

C

Explanation

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Q 22. In the following reaction: Product 'P' will not give

A

Tollen's reagent test

B

Victor Meyer test

D

Iodoform test

Explanation

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Q 23. In the following reaction

The major product is

B

C

D

Explanation

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Q 24. Which of the following acids does not exhibit optical isomerism?

Maleic acid

B

{tex}\alpha {/tex}-amino acids

C

Lactic acid

D

Tartaric acid

Explanation

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Q 25. The number of chain isomers possible for the hydrocarbon {tex} \mathrm { C } _ { 5 } \mathrm { H } _ { 12 } {/tex} is

A

1

B

2

3

D

4