Hydrocarbons · JEE Main previous year questions

2025 10 questions

1. Q572025 · 4 Apr 2025 · Shift 2

   Given below are two statements: Statement (I) : Molal depression constant $K_f$ is given by $\frac{{\mathrm{M}}_1\mathrm{R}{\mathrm{T}}_f}{\Delta {\mathrm{S}}_{\mathrm{fus}}}$, where symbols have their usual meaning. Statement (II) : $K_f$ for benzene is less than the $K_f$ for water. In the light of the above statements, choose the most appropriate answer from the options given below :

   1. A.Statement I is correct but Statement II is incorrect
   2. B.Both Statement I and Statement II are incorrect
   3. C.Statement I is incorrect but Statement II is correct
   4. D.Both Statement I and Statement II are correct
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   Answer: A

2. Q592025 · 3 Apr 2025 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: A

3. Q582025 · 3 Apr 2025 · Shift 2
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: B

4. Q712025 · 3 Apr 2025 · Shift 2· Numerical answer

   $\mathrm{X}\mathrm{g}$ of nitrobenzene on nitration gave $4.2\mathrm{g}$ of $\mathrm{m}$-dinitrobenzene. $\mathrm{X}=$___________g. (nearest integer) $[\text{Given : molar mass (in }{\mathrm{gmol}}^{-1})\mathrm{C}:12,\mathrm{H}:1,\mathrm{O}:16,\mathrm{N}:14]$

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   Answer: 3

5. Q512025 · 29 Jan 2025 · Shift 2

   Given below are two statements : Statement (I): On nitration of m-xylene with $\mathrm{HN}{\mathrm{O}}_3,{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ followed by oxidation, 4-nitrobenzene-1,3-dicarboxylic acid is obtained as the major product. Statement (II) : $-\mathrm{C}{\mathrm{H}}_3$ group is o/p-directing while $-\mathrm{N}{\mathrm{O}}_2$ group is m-directing group. In the light of the above statements, choose the correct answer from the options given below :

   1. A.Statement I is true but Statement II is false
   2. B.Both Statement I and Statement II are true
   3. C.Both Statement I and Statement II are false
   4. D.Statement I is false but Statement II is true
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   Answer: B

6. Q752025 · 29 Jan 2025 · Shift 2· Numerical answer

   Isomeric hydrocarbons $\to$ negative Baeyer's test (Molecular formula ${\mathrm{C}}_9{\mathrm{H}}_{12}$) The total number of isomers from above with four different non-aliphatic substitution sites is -

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   Answer: 2

7. Q562025 · 28 Jan 2025 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: A, D

8. Q722025 · 28 Jan 2025 · Shift 1· Numerical answer
   
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   Answer: 93

9. Q672025 · 24 Jan 2025 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: D

10. Q722025 · 24 Jan 2025 · Shift 2· Numerical answer

    The hydrocarbon (X) with molar mass $80\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ and $90\%$ carbon has ____ degree of unsaturation.

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    Answer: 3