How do you balance disproportionation reactions?
I usually write 2 separate redox reaction: one an oxidation; the other a reduction.
For example, let's take the action of hydroxide on chlorine gas. Chloride ion is produced, a reduction:
But also chlorate ion is produced, an oxidation from
(I add the hydroxides because the reaction was specified to be the action of BASE!)
This is the same as any redox calculation. But here that stuff that is oxidized is the SAME as that which is reduced.