Identify the reagent involved in the Sandmeyer reaction.

The conversion of benzene diazonium chloride to bromobenzene can be accomplished by

Aryl fluoride may be prepared from arene diazonium chloride using

In this process,the product $A$ is:

The chlorobenzene is generally obtained from a corresponding diazonium salt by reacting it with

Write the structures and names of the compounds formed when compound $A$ with molecular formula $C_7H_8$ is treated with $Cl_2$ in the presence of $FeCl_3$.