3 H3O+ + 10 NIIIO2- + 4 MnVIIO4- 9 OH- + 10 NVO3- + 4 (MnII)2+

This is an oxidation-reduction (redox) reaction:

4 MnVII + 20 e- 4 MnII (reduction)

10 NIII - 20 e- 10 NV (oxidation)

MnO4- is an oxidizing agent, NO2- is a reducing agent.