(b) (i) How is Aniline converted into Phenol?
(ii) What is the action of HCN on
(1) propanone (2) 2,4-dichlorobenzaldehyde.

Explanation

(b) (i) Aniline is diazotized with nitrous acid (NaNO2 + HCl) at 273-278K to give benzene diazonium chloride which on further treatment with hot water in the presence of mineral acid gives phenol.

(ii) 1. Propanone reacts with HCN:
`underset(underset(("Acetone"))(("Propanone")))(CH_(3) - underset(underset(O)(||))(C) - CH_(3) + HCN) rarr underset(underset(("Cyanohydrin"))(("Acetone")))(CH_(3) - underset(underset(OH)(|))overset(overset(CN)(|))(C) - CH_(3))`
2. 2,4-dichlorobenzaldehyde reacts with HCN: