5 C2IIIO42- + 2 MnVIIO4- + 16 H+ 10 CIVO2 + 2 (MnII)2+ + 8 H2O

This is an oxidation-reduction (redox) reaction:

2 MnVII + 10 e- 2 MnII (reduction)

10 CIII - 10 e- 10 CIV (oxidation)

MnO4- is an oxidizing agent, C2O42- is a reducing agent.