Aniline on treatment with NaNO ₂ / HCl at about 0^ C gives a compound A, which on further treatment with CuCN / KCN gives a compound B, which when reacts with H ₂ / Ni gives a compound C. The compound C on reaction with HNO ₂ gives a compound D. The structure of D is:

Step-by-step solution

Aniline ( C ₆ H ₅ NH ₂ ) undergoes diazotization with NaNO ₂ and HCl at 0^ C to form benzene diazonium chloride (A). C ₆ H ₅ NH ₂ NaNO ₂ / HCl , 0^ C C ₆ H ₅ N ₂^+ Cl ^- (A) Benzene diazonium chloride reacts with CuCN / KCN to form benzonitrile (B) via the Sandmeyer reaction. C ₆ H ₅ N ₂^+ Cl ^- CuCN / KCN C ₆ H ₅ CN (B) Benzonitrile is reduced by H ₂ / Ni to form benzylamine (C). C ₆ H ₅ CN H ₂ / Ni C ₆ H ₅ CH ₂ NH ₂ (C) Benzylamine, being an aliphatic primary amine, reacts with nitrous acid ( HNO ₂ ) to form benz