Question

Which of the following tests is suitable to differentiate between aniline and benzylamine?

• A. Aniline gives dye test on diazotisation and reaction with $\beta -$naphthol, while benzylamine gives alcohol.
• B. Benzylamine gives green dry with $beta-$naphthol after diazotisation while aniline gives orange dye.
• C. Aniline gives carbylamine reaction while benzylamine does not.
• D. Benzylamine gives carbylamine reaction while aniline does not.

Answer 1

The correct option is A Aniline gives dye test on diazotisation and reaction with $\beta -$naphthol, while benzylamine gives alcohol.

Aniline forms stable diazonium salts when reacted with nitrous acid $HN{O}_2$, and no $N_2$ gas is evolved.

$NaN{O}_2+HCl\to HN{O}_2+NaCl$

$C_6{H}_{5}N{H}_2\stackrel{NaN{O}_2+HCl}{\to }{C}_6{H}_5{N}_{2}C{l}^{-}+NaCl+2H_{2}O$

Benzylamine on reaction with $HN{O}_2$ yeilds Benzyl alcohol and Nitrogen gas.

$C_6{H}_{5}C{H}_{2}N{H}_2\stackrel{HN{O}_2}{\to }\left[C_6{H}_{5}C{H}_2{N}_2^{+}C{l}^{-}\right]\stackrel{H_{2}O}{\to }{C}_6{H}_{5}C{H}_{2}OH+HCl+N_2\left(g\right)$