K2Cr2VIO7 + 14 HCl-I 2 CrIIICl3-I + 3 Cl20 + 2 KCl-I + 7 H2O

This is an oxidation-reduction (redox) reaction:

6 Cl-I - 6 e- 6 Cl0 (oxidation)

2 CrVI + 6 e- 2 CrIII (reduction)

Change the oxidation states