Chlorine can be obtained by which of the following process.

Chlorine gas can be produced by all given reactions.

Formation of chlorine gas from the electrolysis of NaCl is

 $2 \mathrm{NaCl}\left(\mathrm{l}\right) \to 2\mathrm{Na}\left(\mathrm{s}\right) +{\mathrm{Cl}}_2\left(\mathrm{g}\right) \uparrow$

Formation of chlorine gas from HCl and NaClO is:

$\mathrm{NaClO}+2\mathrm{HCl}\to {\mathrm{Cl}}_2\uparrow +{\mathrm{H}}_2\mathrm{O}+\mathrm{NaCl}$

Formation of chlorine gas when HCl and oxygen gas reacts in the presence of CuCl₂ is:

$4\mathrm{HCl}+{\mathrm{O}}_2\stackrel{{\mathrm{CuCl}}_2}{⟶}2{\mathrm{H}}_2\mathrm{O}+2{\mathrm{Cl}}_2\uparrow$