3.The analyte is heated with alcoholic potassium hydroxide and chloroform in carbylamine reaction (Hoffman's isocyanide test). This is done for detecting primary amines. If a primary amine is present, the isocyanide (carbylamine) is formed which are foul smelling substances.

Chloroform,CHCl3 when warmed with silver powder gives acetylene. 2HCl3+ 6Ag---->C2H2(Acetylene)+6AgCl