$\mathrm{C}_6 \mathrm{H}_5 \mathrm{NH}_2 \xrightarrow{\mathrm{HNO}_2}$

$\mathrm{C}_6 \mathrm{H}_5 \mathrm{~N}_2 \mathrm{Cl}+\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH} \xrightarrow{\mathrm{OH}^{-}}$

$\mathrm{C}_6 \mathrm{H}_5 \mathrm{~N}_2 \mathrm{Cl} \xrightarrow{\mathrm{HBr}_4}$

$\quad \mathrm{C}_6 \mathrm{H}_5 \mathrm{~N}_2 \mathrm{Cl} \xrightarrow[\mathrm{HCl}]{\mathrm{Cu} \text { (Powder) }}$