Question

Which of the following amines will not give $N _{2}$ gas on treatment with nitrous acid $\left( NaNO _{2}+ HCl \right)$ ?

• A. $C_2H_5NH_2$
• B. $CH_3NH_2$
• C. $\left( CH _{3}\right)_{2} CH - NH _{2}$
• D. All will give $N_2$

Answer 1

Answer: (D)

All aliphatic primary amines liberate $N_2$ gas on treatment with $HNO_2$ .

$R - NH_2 + HONO \xrightarrow{273-278\, K} R - OH + N_2 + H_2O$

Since no other class of amines liberate $N_2$ gas on treatment with $HNO_2$ , this reaction is used as a test for aliphatic primary amines.