I20 + 7 Cl20 + 12 H2O 2 H5IVIIO6 + 14 HCl-I

This is an oxidation-reduction (redox) reaction:

2 I0 - 14 e- 2 IVII (oxidation)

14 Cl0 + 14 e- 14 Cl-I (reduction)

Change the oxidation states