Question

Primary and secondary amines are distinguished by 

(a) Br₂/KOH 

(b) HCIO 

(c) HNO₂

(d) NH₃

Answer 1

(c) HNO₂

Primary and secondary amines are distinguished by nitrous acid HNO₂.

Primary amines when reacted with nitrous acid forms alcohols and secondary amines when reacted with nitrous acid forms N-nitroso derivative.

1° Amines: 

R − NH₂​ →^HNO₂ ​R - N⁺ ≡ NX^- → R⁺ → R - OH(alcohol)

2° Amines: 

R₂ − NH →^HNO₂ ​R₂ - N - NO(N−nitroso derivative)