2 KMnO4 + 10 NaC2O4 + 8 H2SO4 → 8 H2O + 20 CO2 + K2SO4 + 2 MnSO4 + 5 Na2SO4
This is an oxidation-reduction (redox) reaction:
2 MnVII + 10 e- → 2 MnII (reduction)
20 C7/2 - 10 e- → 20 CIV (oxidation)
KMnO4 is an oxidizing agent, NaC2O4 is a reducing agent.