JEE Main · 2025 · 02 Apr 2025 · Shift 1 · Compounds Containing Nitrogen

Hydrazine is a weaker base than ammonia because its second electronegative nitrogen withdraws density from the lone pair that would bind a proton. Replacing a hydrogen of ammonia by an electron-releasing ethyl group raises the basicity, so ethylamine exceeds ammonia. In water the observed strength reflects both this electron release and the hydrogen-bond stabilisation of the protonated cation; the diethylammonium ion is best stabilised, while triethylamine's crowded nitrogen is poorly solvated, so diethylamine is strongest and triethylamine falls below it. The basic strength thus rises from hydrazine to ammonia to ethylamine to triethylamine and finally to diethylamine.