Question

There is a solution of p-hydroxybenzoic acid and p-amino benzoic acid. Discuss one method by which we can separate them and also write down the confirmatory test of the functional groups present.

Answer 1

For the separation of p-hydroxy benzoic acid and p-aminobenzoic acid with a solution, the solution is treated with HCl. Therefore, p-aminobenzoic acid is remained in solution as form of ammonium salt, while p-hydroxybenzoic acid is not soluble (non-soluble, so it is separated easily)

Test : (2) Azodye test :p-aminobenzoic acid gives azodye test while p-hydroxybenzoic acid does not give azodye test. Test : 

(3) Liebermann nitroso test : p-hydroxy benzoic acid gives Liebermann nitroso test, while p-amino benzoic acid does not give Liebermann nitroso test.