In the above chemical reaction, intermediate ''X'' and reagent/condition ''A'' are :

Solution

Chemistry ma’am · 3 steps

Cold NaNO₂/HCl on aniline means diazotisation. Warming that salt in water swaps N₂ for OH.

1. Identify X. NaNO₂ and HCl together make nitrous acid, HNO₂. At 273 to 278 K it turns a primary aromatic amine into a diazonium salt, so X is benzenediazonium chloride, C₆H₅N₂⁺Cl⁻.

   C₆H₅NH₂ + NaNO₂ + 2HCl →(273-278 K) C₆H₅N₂⁺Cl⁻ + NaCl + 2H₂O

2. Identify A. The diazonium salt is stable only in the cold. When its aqueous solution is warmed, N₂ leaves as a gas and water supplies the OH group, so phenol forms. A is therefore H₂O with heat.

   C₆H₅N₂⁺Cl⁻ + H₂O →(Δ) C₆H₅OH + N₂ ↑ + HCl

3. So. X is benzenediazonium chloride and A is H₂O/Δ, which is option (d).

The idea to keep. Aniline plus NaNO₂/HCl at 0 to 5 °C always gives the diazonium salt. To get phenol, warm it in water, which is a mildly acidic medium. Alkali sends a diazonium salt towards coupling instead.

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