MHTCET 20 Apr 2026 Shift 2 Paper

Concept:The Hinsberg test uses an aryl sulphonyl chloride to distinguish amines based on the solubility of the resulting sulphonamide in alkali.Explanation:The reagent employed in the Hinsberg test is benzenesulphonyl chloride, $\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{SO}_{2}\mathrm{Cl}$.When a primary amine reacts with this reagent, it forms a sulphonamide that contains an acidic hydrogen atom attached to the nitrogen.Because of this acidic hydrogen, the sulphonamide derived from a primary amine dissolves readily in an aqueous alkali solution.In contrast, a secondary amine reacts to form a sulphonamide which lacks this acidic hydrogen.Consequently, the secondary amine derivative remains insoluble in aqueous alkali.This clear-cut difference in the solubility behaviour of the sulphonamide derivatives effectively distinguishes primary and secondary amines.Answer:The correct option is $C$, which is $\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{SO}_{2}\mathrm{Cl}$ (benzenesulphonyl chloride).