6 I20 + 6 Ba(OH)2 Ba(IVO3)2 + 5 BaI2-I + 6 H2O

This is an oxidation-reduction (redox) reaction:

10 I0 + 10 e- 10 I-I (reduction)

2 I0 - 10 e- 2 IV (oxidation)

Change the oxidation states