Cr2VIO72- + 14 H+ + 6 (I-I)- 2 (CrIII)3+ + 3 I20 + 7 H2O

This is an oxidation-reduction (redox) reaction:

6 I-I - 6 e- 6 I0 (oxidation)

2 CrVI + 6 e- 2 CrIII (reduction)

Change the oxidation states