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

Options

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

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, gas + alcohol formation
`R-NH_2+HNO_2toR-overset(+)NNequiv NCl^-overset(H_2O)toROH+N_2+HCl`
Reaction of nitrous acid with aromatic amines Liberation of `N_2` gas + Phenol formation
`PhNH_2+HNO_2+HCloverset(273-278)toPh-overset(+)Nequiv NCl^(-)toPhOH+HCl+N_2`
Reaction of nitrous acid with `2circ` amines With `HNO_2`, they give nitroso amines, which being insoluble in dilute acids separate as yellow oily compound.
`R_2NH+HONOtoR_2-N-N=O`
N-nitroso dialkyl amine (yellow oil)
Reaction of nitrous acid with `3^circ` amines
Aliphatic `3^circ` amines on reaction with HONO form soluble nitrite salts, while aromatic `3^circ` amines form green coloured p -nitroso amines.
`R_3N+HONOto[R_3overset(+)NH]NO_2^-` (Soluble nitrite)