HClVO3 + 3 H2O2-I 3 O20 + HCl-I + 3 H2O

This is an oxidation-reduction (redox) reaction:

ClV + 6 e- Cl-I (reduction)

6 O-I - 6 e- 6 O0 (oxidation)

HClO3 is an oxidizing agent, H2O2 is a reducing agent.