c
\(\underset{\begin{smallmatrix}   \,\text{Benzene} \\   \text{diazoniumchloride}  \end{smallmatrix}}{\mathop{{{C}_{6}}{{H}_{5}}{{N}_{2}}Cl}}\,\,\,\xrightarrow[or\,Cu+HCl]{CuCl/HCl}\,\underset{\text{Chloro benzene}}{\mathop{{{C}_{6}}{{H}_{5}}Cl}}\,\,\,+\,{{N}_{2}}\) The above reaction is known as Sandmayer 's reaction.