Identify the product A in the following reaction.

Solution

Chemistry ma’am · 4 steps

Follow the group on the ring step by step: NH₂ becomes N₂⁺, then Cl, then OH.

1. Diazotisation. NaNO₂ + HCl at 273 to 278 K turns aniline into benzenediazonium chloride, C₆H₅N₂⁺Cl⁻. The -NH₂ group is now -N₂⁺.
2. Sandmeyer reaction. Cu₂Cl₂ replaces the -N₂⁺ group with Cl, and nitrogen gas leaves. You get chlorobenzene, C₆H₅Cl. The Cl takes the place of the old group, so nothing new is added at the para position.
3. Dow process. Aryl halides resist substitution, so you need NaOH at 623 K and 300 atm. Under these harsh conditions OH replaces Cl, giving sodium phenoxide, C₆H₅O-Na⁺.

   C₆H₅NH₂ →(NaNO₂/HCl) C₆H₅N₂⁺Cl⁻ →(Cu₂Cl₂) C₆H₅Cl →(NaOH, 623 K) C₆H₅ONa →(H⁺) C₆H₅OH

4. So. Acid converts sodium phenoxide to phenol. The ring carries only one group at the end, so A is phenol, option (b).

The idea to keep. Diazonium salts let you swap -NH₂ for almost anything. Each later step replaces that same group, and no new group is added. Aniline to chlorobenzene to phenol is a classic route.

Answer from the NTA final answer key. Solution by PrepWiser.