Question

Which one of the following substances react with nitrous acid to give a hydroxy compound?

• A. $C _{2} H _{5} NH _{2}$
• B. $\left( C _{2} H _{5}\right)_{2} NH$
• C. $C _{6} H _{5} NH _{2}$
• D. Both(a) and (c)

Answer 1

Answer: (A)

To distinguish $1^{\circ}, 2^{\circ}$ and $3^{\circ}$ amine we use $HNO _{2}$ reaction.

$\left(1^{\circ}\right) R - NH _{2}+ HNO _{2} \rightarrow R - OH + N _{2}+ H _{2} O$

$\left(2^{\circ}\right) R _{2} NH + HNO _{2} \rightarrow \underset{\text{nitrosoamines}}{R _{2} NNO + H _{2} O}$

$\left(3^{\circ}\right) R _{3} N + HNO _{2} \rightarrow \underset{\text{trialkyl ammonium nitrite}}{R _{3} NH ^{+} ONO ^{-}}$