Hydrocarbons · JEE Main previous year questions

2026 9 questions

1. Q632026 · 6 Apr 2026 · Shift 1

   $R_f$ value for 2-methylpropene in a solvent system (Ethyl acetate + ether) is 0.42. 2-methylpropene is treated with dilute ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ to give major organic product (X). $R_f$ value for (X) in the same solvent system under identical condition will be:

   1. A.0.42
   2. B.0.82
   3. C.0.62
   4. D.0.12
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   Answer: D

2. Q642026 · 5 Apr 2026 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: D

3. Q652026 · 5 Apr 2026 · Shift 1
   
   1. A.A and D only
   2. B.B and C only
   3. C.A and C only
   4. D.B and D only
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   Answer: B

4. Q642026 · 4 Apr 2026 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: D

5. Q562026 · 4 Apr 2026 · Shift 2

   Match the LIST-I with LIST-II $$\begin{array}{ll}\text{List-I}& \text{List-II}\\ \text{Reaction}& \text{Mechanism}\\ \text{A. Williamson Synthesis}& \text{I. Electrophilic addition}\\ \text{B. Friedel Craft Reaction}& \text{II. Free radical substitution}\\ \text{C. Bromination of vinyl benzene}& \text{III. Nucleophilic substitution}\\ \text{D. Chlorination of toluene in light}& \text{IV. Electrophilic substitution}\end{array}$$ Choose the correct answer from the options given below:

   1. A.A-III, B-I, C-II, D-IV
   2. B.A-III, B-IV, C-II, D-I
   3. C.A-III, B-IV, C-I, D-II
   4. D.A-I, B-III, C-IV, D-II
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   Answer: C

6. Q642026 · 2 Apr 2026 · Shift 2

   The compound (X) on (i) on heating in the presence of anhydrous $\mathrm{AlC}{\mathrm{l}}_3$ and $\mathrm{HCl}$ gas gives 2,4-dimethyl pentane (ii) aromatization gives toulene and (iii) cyclisation gives methyl cyclohexane The correct name of compound (X) is :

   1. A.Hept-2-ene
   2. B.Hept-1,3,5-triene
   3. C.Heptane
   4. D.Hept-2,4,6-triene
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   Answer: C

7. Q692026 · 28 Jan 2026 · Shift 2

   Identify the correct statements : The presence of $-{\text{NO}}_2$ group in benzene ring A. activates the ring towards electrophilic substitutions. B. deactivates the ring towards electrophilic substitutions. C. activates the ring towards nucleophilic substitutions. D. deactivates the ring towards nucleophilic substitutions. Choose the correct answer from the options given below :

   1. A.A and D Only
   2. B.B and D Only
   3. C.C and A Only
   4. D.B and C Only
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   Answer: D

8. Q542026 · 24 Jan 2026 · Shift 1
   
   1. A.III > I > II > IV
   2. B.III > II > I > IV
   3. C.I > III > II > IV
   4. D.I > III > IV > II
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   Answer: C

9. Q532026 · 22 Jan 2026 · Shift 1

   Given below are two statements : Statement I : Benzene is nitrated to give nitrobenzene, which on further treatment with $\mathrm{C}{\mathrm{H}}_{3}COCl/AlC{\mathrm{l}}_3$ will give [structure: benzene ring with $\mathrm{COC}{\mathrm{H}}_3$ and $\mathrm{N}{\mathrm{O}}_2$ meta to each other] Statement II : $-\mathrm{N}{\mathrm{O}}_2$ group is a $m$-directing, and deactivating group. In the light of the above statements, choose the most appropriate answer from the options given below

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