The amine 'A' when treated with nitrous acid gives yellow oily substance. The amine A is

Options

A. triethylamine
B. trimethylamine
C. aniline
D. methyphenylamine

Answer

D

Explanation

Secondary amines when treated with nitrous acid give yellow oily substance. So, amine 'A' is methylphenyl amine.
Reaction of nitrous acid with aliphatic amines
Liberation of `N_2` gas + alcohol formation
`R-NH_2+HNO_2 to R - overset+N -=NCl^(-) overset(H_2O)to ROH + N_2+HCl`
Reaction of nitrous acid with aromatic amines
Liberation of `N_2` gas + Phenol formation
`PhNH_2+HNO_2 + HCl overset(273-278 K) to Ph-overset+N -= HCl^(-) to PhOH + HCl + N_2`
Reaction of nitrous acid with `2^@` amines With `HNO_2`, they give nitroso amines , which being insoluble in dilute acids separate as yellow oily compound.
`R_2NH+ HONO to R_2 - N - N =O `
N- nitroso dialkyl amine (yellow oil)
Reaction of nitrous acid with `3^@` amines
Aliphatic `3^@` amines on reaction with HONO form soluble nitrite salts , while aromatic `3^@` amines from green coloured p-nitroso amines.
`R_3N + HONO to underset"(Soluble nitrite )"([R_3 overset+NH ] NO_2^-)`