Question

What happens when benzene diazonium chloride is treated with an aqueous solution of potassium iodide?

Answer 1

When benzene diazonium chloride (C₆H₅N₂Cl) is treated with an aqueous solution of potassium iodide (KI), a substitution reaction occurs where the diazonium group \[\ce{(-N^+_2)}\] is replaced by an iodine atom (I). This is known as the Sandmeyer reaction.

1. Benzene diazonium chloride reacts with KI solution to give iodobenzene (C₆H₅I) along with nitrogen gas (N₂) and potassium chloride (KCl).
2. The nitrogen gas is released as a by-product.
3. This reaction proceeds via the formation of an intermediate aryl diazonium ion, which is replaced by an iodide ion from KI.
   

This reaction is useful to synthesize iodoaromatic compounds from aromatic amines via diazonium salts.