Question

Reaction of aniline with $$\text{HN}{\text{O}}_{\text{2}}$$ followed by treatment of dilute acid gives:
A) $${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{NHOH}$$
B) $${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{OH}$$
C) $${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{NHN}{\text{H}}_{\text{2}}$$
D) $${\text{C}}_{\text{6}}{\text{H}}_6$$

Answer 1

Hint:Aniline reacts similarly to primary aliphatic amines. Aniline gives diazonium ion after treatment with nitrous acid. On further treatment with dilute acid undergo hydrolysis reaction.

Complete solution:
In this reaction, aniline is the reactant and reagent given to us is nitrous acid, $$\text{HN}{\text{O}}_{\text{2}}$$ and dilute acid.
Aniline is the simplest aromatic amine that behaves similarly to primary aliphatic amines. It consists of an amino group bonded to a phenyl group.
Reagent nitrous acid is prepared by reaction of sodium nitrite with hydrochloric acid. It is a weak acid
$$\text{NaN}{\text{O}}_{\text{2}}\text{ + HCl}\to \text{ NaCl + HN}{\text{O}}_{\text{2}}$$
Now, we will see the reaction mechanism when of aniline reacts with $$\text{HN}{\text{O}}_{\text{2}}$$ followed by treatment with dilute acid.
Step 1: Conversion of aniline to diazonium ion using nitrous acid, $$\text{HN}{\text{O}}_{\text{2}}$$reagent.

Step 2: Diazonium ion on further treatment with dilute acid undergoes hydrolysis reaction and gives phenol as the product.

Thus, the correct options are (B).

Note:Aromatic diazonium ion is a very important intermediate to produce substituted benzene. The final product depends on reagent use. Here the reagent used is dilute acid so the diazonium ion undergoes a hydrolysis reaction. The addition of water molecules is known as the hydrolysis reaction. Amines on hydrolysis give alcohol as the product while aniline gives phenol as the product.