A-Level Chemistry - Disproportionation Reaction

In cold dilute aqueous NaOH, chlorine reacts with NaOH in a disproportionation reaction.
\( \text{Cl}_2\text{(aq)} + 2\text{NaOH(aq)} \rightarrow \text{NaCl(aq)} + \text{NaClO(aq)} + \text{H}_2\text{O(l)} \)
One Cl atom is oxidised from 0 to +1. The other is reduced from 0 to -1. In other words:
\( \text{Cl} + e^- \rightarrow \text{Cl}^- \)
\( \text{Cl} \rightarrow \text{Cl}^+ + e^- \)
In hot concentrated aqueous NaOH, ClO3− (chlorate (V)) ions are produced instead of ClO- (hypochlorite).
\( 3\text{Cl}_2\text{(aq)} + 6\text{NaOH(aq)} \rightarrow 5\text{NaCl(aq)} + \text{NaClO}_3\text{(aq)} + 3\text{H}_2\text{O(l)} \)
5 Cl atoms are reduced from 0 to -1. One Cl atom is oxidised from 0 to +5.
\( 5\text{Cl} + e^- \rightarrow 5\text{Cl}^- \)
\( \text{Cl} \rightarrow \text{Cl}^{5+} + 5e^- \)