JEE Main · 2020 · 03 Sep 2020 · Shift 2 · Compounds Containing Nitrogen

All three isomers share the formula $C_8{H}_{11}N$, which fits aromatic amines carrying two further carbons as alkyl groups. Compound A reacts with nitrous acid to give two products R and S of different boiling point, the behaviour of a primary amine whose diazonium chemistry leads to more than one product. Compound B treated with benzenesulfonyl chloride, Hinsberg's reagent, gives a product that does not dissolve in alkali, the response of a tertiary amine, which has no N-H to form an alkali-soluble sulfonamide. These tests fix A as the primary amine, B as the tertiary amine, and C as the remaining secondary isomer, identifying the three structures in that order.