The mixture of amines is treated with benzene sulphonyl chloride (Hinsberg's reagent) and shaken with alkali solution.(1) Primary amine forms alkyl benzenesulphonamide which dissolves in alkali to form sodium or potassium salt of monoalkylbenzenesulphonamide.\\\\(\\displaystyle PhSO_2Cl + HNHR \\rightarrow PhSO_2NHR \\xrightarrow {KOH} PhSO_2NKR \ ext {(water soluble)}\\\\)(2) Secondary amine forms alkyl sulphonamide which does not form salt with alkali and hence remains insoluble (solid) in alkali solution.\\\\(\\displaystyle PhSO_2Cl + HNR_2 \\rightarrow PhSO_2NR_2 \ ext {(water insoluble)} \\rightarrow \ ext { no action}\\\\)(3) Tertiary amines does not react with Hinsberg's reagent.\\\\(\\displaystyle PhSO_2Cl + NR_3 \\rightarrow \ ext { no reaction}\\\\)