Question

Prepare carbolic acid from benzene sulphonic acid. Write a chemical equation for the action of neutral ferric chloride on phenol.

Answer 1

Preparation of carbolic acid (phenol) from benzene sulphonic acid:

Treatment of benzene sulphonic acid with NaOH gives sodium salt of benzene sulphonic acid. This sodium salt is heated with NaOH at ${350}^0$ to form sodium salt of phenol. The acid hydrolysis of sodium salt gives phenol.

The action of neutral ferric chloride on phenol gives violet coloured complex.