The product A formed in the following reaction is:

Step-by-step solution

Diazotization: The process of conversion of a primary aromatic amino compound into a diazonium salt is known as diazotization. This process is carried out by adding an aqueous solution of sodium nitrite to a solution of primary aromatic amine (e.g., aniline) in excess of HCl at a temperature below 5 ° C . Decomposition of benzene diazonium chloride by using Cu 2 Cl 2 / HCl to form chlorobenzene is known as sandmeyer's reaction.