14 HCl2 + K2Cr2O7 → 2 CrCl3 + 2 KCl + 10 Cl2 + 7 H2O
This is an oxidation-reduction (redox) reaction:
14 HII + 14 e- → 14 HI (reduction)
20 Cl-I - 20 e- → 20 Cl0 (oxidation)
2 CrVI + 6 e- → 2 CrIII (reduction)
HCl2 is an oxidizing agent, HCl2 is a reducing agent, K2Cr2O7 is an oxidizing agent.