Which of the following reactions is exhibited only by primary amines?

Step-by-step solution

Acetylation is given by both primary and secondary amines as they contain replaceable hydrogen atoms on the nitrogen atom. Alkylation is given by primary, secondary, and tertiary amines to form higher amines and quaternary ammonium salts. Reaction with nitrous acid is given by primary, secondary, and tertiary amines, though they yield different products (primary amines yield alcohols or diazonium salts, secondary amines yield N-nitrosamines, and tertiary amines yield nitrite salts). The carbylamine test (isocyanide