Aliphatic and aromatic primary and secondary amines react with acid chlorides, anhydrides and esters by nucleophilic substitution reaction. This reaction is known as acylation. You can consider this reaction as the replacement of hydrogen atom of –NH2 or >N–H group by the acyl group. The products obtained by acylation reaction are known as amides. The reaction is carried out in the presence of a base stronger than the amine, like pyridine, which removes HCl so formed and shifts the equilibrium to the right hand side.
What is the product formed when aniline reacts with benzoyl chloride in the presence of a base?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → N-Phenylbenzamide
In acylation an acyl group replaces one H of the –NH2 group and an amide is formed. With benzoyl chloride the acyl group is the benzoyl group (\( \ce{C6H5CO-} \)), and the reaction is called benzoylation; the base removes the HCl formed.
\( \displaystyle \ce{C6H5NH2 + C6H5COCl} \xrightarrow{\text{base}} \ce{C6H5NHCOC6H5 + HCl} \)
The product is benzamide (\( \ce{C6H5CONH2} \)) with a phenyl group on its nitrogen: N-phenylbenzamide.
Why the other options are incorrect
Option (1) Acetanilide — Incorrect. It carries an acetyl group (\( \ce{CH3CO-} \)); it forms with acetyl chloride or acetic anhydride, not with benzoyl chloride.
Option (3) N-Phenylbenzenesulphonamide — Incorrect. A sulphonamide forms with benzenesulphonyl chloride (\( \ce{C6H5SO2Cl} \)), which has an \( \ce{-SO2-} \) group, not a C=O group.
Option (4) No reaction — Incorrect. Aniline is a primary amine with H atoms on nitrogen, so it is acylated.
NCERT (2026-27 edition):
9.6 Chemical Reactions
