5 Na2C2IIIO4 + 2 KMnVIIO4 + 16 HCl 2 MnIICl2 + 2 KCl + 10 NaCl + 10 CIVO2 + 8 H2O

This is an oxidation-reduction (redox) reaction:

2 MnVII + 10 e- 2 MnII (reduction)

10 CIII - 10 e- 10 CIV (oxidation)

KMnO4 is an oxidizing agent, Na2C2O4 is a reducing agent.