JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Practical and Analytical Chemistry

A primary amine (ethylamine) gives the carbylamine reaction with chloroform and alcoholic KOH on heating, forming a foul-smelling isocyanide, whereas the secondary amine diethylamine does not, so that pair is told apart by $\mathrm{CHC}{\mathrm{l}}_3+\mathrm{KOH},\Delta$. An aldehyde (acetaldehyde) gives a silver mirror with ammoniacal silver nitrate while the ketone acetone does not, so that pair is distinguished by ammoniacal silver nitrate. Phenol gives a violet colour with neutral $\mathrm{FeC}{\mathrm{l}}_3$ but ethanol does not, separating that pair. Cinnamic acid contains a $\mathrm{C}=\mathrm{C}$ bond and decolourises bromine water, while benzoic acid does not, distinguishing that pair. The matching is A-II, B-IV, C-III, D-I.