MCQMediumJEE 2023Alkyl Halides

JEE Chemistry 2023 Question with Solution

The major products 'A' and 'B', respectively, are:

Reaction scheme showing 2-methylpropene forming product A with cold sulfuric acid and product B with sulfuric acid at 80 degree Celsius.
  • A
    Option showing tert-butyl hydrogen sulfate as first product and 2,4,4-trimethylpent-2-ene as second product.
  • B
    Option showing 2,4,4-trimethylpent-2-ene as first product and tert-butyl hydrogen sulfate as second product.
  • C
    Option showing a longer-chain alkane-type product as first compound and tert-butyl hydrogen sulfate as second product.
  • D
    Option showing tert-butyl hydrogen sulfate as first product and a longer-chain branched alkane-type product as second compound.

Answer

Correct answer:B

Step-by-step solution

Standard Method

Given: The alkene shown reacts with cold H2SO4\mathrm{H_2SO_4} to form A and with H2SO4\mathrm{H_2SO_4} at 80C80^\circ\text{C} to form B.

Find: The major products A and B respectively.

In the given reaction, electrophilic substitution of the phenyl group with a sulfate group is induced. The major products are:

Solution image showing A as tert-butyl hydrogen sulfate and B as 2,4,4-trimethylpent-2-ene, matching option B.

Therefore, the correct option is B.

Common mistakes

  • Assuming the answer key key is always correct. Here the provided answer key says (1), but the solution explicitly concludes option B. The solution working is the primary source, so use the solution conclusion.

  • Reversing the products A and B. The conditions are different: cold H2SO4\mathrm{H_2SO_4} and 80C80^\circ\text{C} do not give the same major product order. Match each product carefully with its corresponding condition.

  • Ignoring the role of reaction conditions in alkene reactions. Temperature and acid conditions affect whether addition or further rearranged product formation becomes major. Always connect the product to the specific condition written over the arrow.

Practice more Alkyl Halides questions

Get unlimited AI-adaptive practice, mastery tracking, and an AI tutor that explains every step — free to start.

Related questions