Concentrated aqueous sodium chloride can be electrolysed in the laboratory using graphite electrodes. Write half-equations to show the reaction at the cathode.

Concentrated aqueous sodium chloride can be electrolysed in the laboratory using graphite electrodes. The chlorine produced at the anode can react with warm concentrated sodium hydroxide:

${\mathrm{Cl}}_2+6\mathrm{NaOH}\stackrel{ }{\to }5\mathrm{NaCl}+{\mathrm{NaClO}}_3+3{\mathrm{H}}_2\mathrm{O}$

Deduce the oxidation number changes per atom of chlorine when ${\mathrm{Cl}}_2$ is converted to $\mathrm{NaCl}$.

Concentrated aqueous sodium chloride can be electrolysed in the laboratory using graphite electrodes. The chlorine produced at the anode can react with warm concentrated sodium hydroxide:

${\mathrm{Cl}}_2+6\mathrm{NaOH}\stackrel{ }{\to }5\mathrm{NaCl}+{\mathrm{NaClO}}_3+3{\mathrm{H}}_2\mathrm{O}$

Deduce the oxidation number changes per atom of chlorine when ${\mathrm{Cl}}_2$ is converted to ${\mathrm{NaClO}}_3$.