Which amine forms a precipitate insoluble in NaOH with benzenesulphonyl chloride?
Secondary amines like CH₃CH₂NHCH₃ form sulphonamides insoluble in alkali in the Hinsberg test, as per the PDF.
Ref: NCERT Class 12 Chemistry > Chapter 13: Amines > Topic: Chemical Reactions - Alkylation, Acylation and Electrophilic Substitution