Correct Answer - C
Key Idea (i) Presence of electron withdrawing substituent decreases the basicity while the presence of electron releasing substituent like, `-CH_(3), -C_(2)H_(5)`, etc, increases the acidity.
(ii) `HNO_(2)` converts`-NH_(2)` group of aliphatic amine into -OH while that of aromatic amines into -N=NCl.
Since, phenyl group is a electron withdrawing group, it decreases the basicity. Alkyl group, on the other hand, being electron releasing, increases the basicity. Thus, alkyl amines are more basic as compared to aryl amines as well as ammonia.
`R-underset("Alkyl amine")(NH_(2)) overset(HNO_(2))to R-OH`
Thus, `HNO_(2)` (nitrous acid) converts alkyl amines to alcohls.
But aryl amines react with nitrous acid to form diazonium salt.
`underset("Aryl amine")(C_(6)H_(5)NH_(2)) underset(0.5.^(@)C(273-278K))overset(HNO_(2))to C_(6)H_(5)-N_(2)^(+)Cl`
at `0.5^(@)C` temperature
`NaNO_(2)+HCl to HNO_(2) +NaCl`
Thus, `HNO_(2)` does not convert aryl amines into phenol.
