See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the starting material: The starting compound is 4-nitrophenol (p-nitrophenol), which has an OH group and a NO2 group at para positions on a benzene ring. Step 2 - Reaction A (H2/Pd): Catalytic hydrogenation with H2 over Pd reduces the nitro group (-NO2) to an amino group (-NH2). The OH group is unaffected under these mild conditions. Product (A) is 4-aminophenol (p-aminophenol), which has OH and NH2 groups at para positions. Step 3 - Reaction B (Acetic anhydride): Acetic anhydride reacts selectively with the more nucleophilic amino group (-NH2) rather than the phenolic -OH group (amines are better nucleophiles than phenols toward acylation under mild conditions). The -NH2 undergoes acetylation to form -NH-C(=O)-CH3 (acetamido group). The -OH group remains intact. Step 4 - Product identification: The product has a benzene ring with an -OH group and an -NH-C(=O)-CH3 (acetamido) group at para positions. This is 4-acetamidophenol, which is indeed Paracetamol (acetaminophen). Step 5 - Matching to options: - Option (a) shows O-acetylation (ester formation) at OH and free NH2 - incorrect product. - Option (b) shows OH intact and -NH-C(=O)-CH3 (acetamido) at para position - this is correct Paracetamol structure. - Option (c) shows both OH and NH2 remaining with a ketone group - incorrect. - Option (d) shows NH2 and OH without acetylation - this is just 4-aminophenol (compound A), not B. Therefore, the correct answer is B.