JEE Main 2025 Jan 23 Shift 1, Chemistry Q20: Analysis of Amines

Hinsberg's reagent (benzenesulphonyl chloride, $PhS{O}_{2}Cl$) requires a replaceable N-H bond. Only primary and secondary amines have N-H bonds, so only they react. Tertiary amines have no N-H, so they do not react.

Classifying the given amines:

(A) Aniline: $1^{\circ }$ - reacts.

(B) N,N-dimethylaniline: $3^{\circ }$ - does not react.

(C) Methylamine: $1^{\circ }$ - reacts.

(D) Trimethylamine: $3^{\circ }$ - does not react.

(E) Diphenylamine: $2^{\circ }$ - reacts.

$\therefore$ A, C, and E react.