Question

Name of the reaction is: $Phenol\xrightarrow{{NaN{O_2}/{H_2}S{O_4}}}B\xrightarrow{{{H_2}O}}C\xrightarrow{{NaOH}}D$.
(A) Liebermann’s Reaction
(B) Phthalein fusion test
(C) Reimer Tiemann Reaction
(D) Schotten-Baumann reaction

Answer 1

In order to tell which reaction is taking place, we must be aware of some of the basic organic reactions which are taking place. We should also remember what are the reagents used in different reactions.

Complete Solution :
Let us now move onto the given question. In the first step phenol with the chemical formula of ${C_6}{H_5}OH$ will be reacting with sodium nitrite and sulphuric acid to give a product called p-Nitroso phenol. The formed p-Nitroso phenol will react with the concentrated sulphuric acid and phenol to form the product B. The product B formed is the Phenol indophenol hydrogen sulphate, which is deep blue in colour. The product which is formed will undergo hydrolysis to give a product C which is Phenol indophenol, which is red in colour. This phenol indophenol will react with NaOH to give a product D which is Sodium salt of phenol indophenol which is also deep blue in colour. This reaction is known as the Liebermann reaction.

So, the correct answer is “Option A”.

Note: We have to remember that the Liebermann test is one of the important methods which is used to detect the presence of the phenol group. The formation of the blue green colour will indicate that the phenol group is present.