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JEE Main 2025 Apr 4 Shift 1, Chemistry Q13: Properties of Alkyl Halides (Halo Alkanes) & Aryl Halides (Halo Arenes)

JEE Main2025Apr 4, Shift 1Chemistry
Q.

Benzene is treated with oleum to produce compound (X) which when further heated with molten sodium hydroxide followed by acidification produces compound (Y). The compound Y is treated with zinc metal to produce compound (Z). Identify the structure of compound (Z) from the following option.

  1. A

    1

  2. B

    2

  3. C

    3

  4. D

    4

Solution

Step 1: Benzene + oleum gives benzenesulphonic acid (X), through electrophilic sulphonation.

Step 2: X with molten NaOH followed by acidification undergoes alkali fusion to give phenol (Y).

Step 3: Phenol heated with zinc dust loses the CO bond and the oxygen is removed as ZnO, regenerating benzene. This is the classical Zn-dust distillation used to confirm the presence of a phenolic OH.

Compound Z is benzene, option (2).

Concept behind this question

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