Question

How will you prepare chlorobenzene from benzene diazonium chloride?

Answer 1

Hint: We know that when a diazonium salt is treated with copper (I)chloride $\left( {C{u_2}C{l_2}} \right)$ or copper (I) bromide $\left( {C{u_2}B{r_2}} \right)$, the corresponding haloarene is formed. This reaction is known as the Sandmeyer reaction. It is used for introducing a chloro or bromo group in the benzene ring.

Complete step by step answer:
According to the question we have to state how chlorobenzene will be prepared from benzene diazonium chloride by the Sandmeyer reaction.
Hence , The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts. This reaction is named after the Swiss chemist Traugott Sandmeyer.
The Sandmeyer reaction is a method for substitution of an aromatic amino group by preparation of its diazonium salt followed by its displacement with a nucleophile, often catalyzed by copper (I) salts. The nucleophile can include halide anions, cyanide , thiols, water and others.
The substitution of an aromatic amino group is possible by preparation of its diazonium salt and successively displacement with a nucleophile. General reaction equation of formation of diazonium salt and haloarenes given below:

For the given question, reaction of preparation of chlorobenzene from diazonium chloride as follows :

Note:Benzene diazonium salt is formed by treating an aromatic primary amine with $NaN{O_2}$ and dil. $HCl$ at low temperature. The process is known as diazotization. Diazonium salts are highly reactive compounds. They are used in the preparation of a large number of arene derivatives. The Sandmeyer reaction helps us to provide a method through which we can perform unique transformations on benzene for example halogenation, cyanation , sulphonation and hydroxylation.