Reaction of aliphatic primary amine with chloroform and enhanolic potassium hydroxide leads to the formation of isocyanides/ carbylamines. This reaction is called carbylamine reaction.
R−NH2→KOH(alc)CHCl3 R - N≡C
This is the confirmatory test for primary amines. A foul smelling isocyanide is formed.
R=−CH3