Consider the following sequence of reactions: Aniline is treated with acetic anhydride in the presence of pyridine to form A . Compound A is then reacted with a mixture of conc. HNO₃ and conc. H₂SO₄ at 288 K to yield a major product B . B is heated with aqueous acid ( H₂O/H^+ ) to give C . Compound C is treated with NaNO₂ and HCl at 273 K to form D . Finally, D is warmed with aqueous KI to yield the final product E .

Step-by-step solution

Aniline reacts with acetic anhydride in pyridine to form acetanilide ( A ). This step protects the amino group. Nitration of acetanilide ( A ) with conc. HNO₃ and conc. H₂SO₄ yields p-nitroacetanilide as the major product ( B ) due to steric hindrance at the ortho position. Acidic hydrolysis of p-nitroacetanilide ( B ) removes the acetyl group, yielding p-nitroaniline ( C ). Treatment of p-nitroaniline ( C ) with NaNO₂ and HCl at 273 K results in diazotization, forming p-nitrobenzenediazonium chloride ( D ). Warmin