1. According to the explanation given in our previous session, in this question we have the following reaction:
MnO4- + C2O42- -> MnO2 + CO2
O = 2-
MnO4- = we have an overall charge of -1, 4 oxygens, therefore we will have -8, and Mn must be = 7+
Mn (reactant) = 7+
C2O42- = overall charge -2, 4 oxygens = -8, therefore carbon must give a final value of +6, since we have 2 carbons, the oxidation number will be +3
C (reactant) = 3+
Mn (products) = 4+
C (products) = 4+
Now for the balanced redox equation:
2 MnO4- + 3 C2O42- + 4 H2O -> 2 MnO2 + 6 CO2 + 8 OH-