Distinction between pairs of compounds
Aniline and N, N-dimethylaniline
1. Carbylamine test.
2. Reaction with Hinsberg's reagent.

Explanation

Aniline on heating with chloroform and alkali gives an unpleasant smell of carbylamine.
`C_(6)H_(5)NH_(2)+CHCl_(3)+3KOHrarrundersetunderset(("Unpleasant smell"))("Phenyl carbylamine")(C_(6)H_(5)Noverset(rarr)=C+)3KCl+3H_(2)O`
This test is not given by dimethylaniline.
Aniline on treatment with Hinsberg.s reagent gives a product which is soluble in alkali whereas dimethylaniline has no reaction with Hinsberg.s reagent.
`C_(6)H_(5)NH_(2)+ClSO_(2)C_(6)H_(5)overset(-HCl)rarrC_(6)H_(5)N.underset(H)underset(|)(S)O_(2)C_(6)H_(5)-H_(2)Ooverset(NaOH)rarrNa^(+)underset(("Water soluble"))([C_(6)H_(5)overset(+)NSO_(2).C_(6)H_(5)])`