I'm looking at an exam question and it says that
2SO42- --> S2O82-
is an oxidation half reaction.
When I work out the charges, they come out equal on both sides. I know that the gain of oxygens may also be a clue, but my question is...do you include the balancing 2 in the first sulphate when you figure out oxidation numbers? I did when I tried to figure out this question, but in the answer explanation, they did not.
Thanks.