MnO
4- Mn
2+ this half reaction needs [H
+] or [H
3O
+] on the left side
H
2O
2 is oxidized
then forms water H
2O and oxygen O
2That's all.
But this reaction has hidden agenda. Mn
2+ catalytically decomposes H
2O
2. This means you can add hydrogen peroxide on the left side obtaining additional water and oxygen on the right side. In this manner you can form infinity numbers of balanced reactions.