How can you prepare $Cl_2$ from $HCl$ and $HCl$ from $Cl_2$? Write reactions only.

(N/A) $(i)$ $Cl_2$ can be prepared from $HCl$ by Deacon's process:
$4HCl + O_2 \xrightarrow{CuCl_2} 2Cl_2 + 2H_2O$
$(ii)$ $HCl$ can be prepared from $Cl_2$ by reaction with water:
$Cl_2 + H_2O \to HCl + HOCl$