2 CrI3 + 64 KOH + 27 Cl2 → 2 K2CrO4 + 6 KIO4 + 54 KCl + 32 H2O
This is an oxidation-reduction (redox) reaction:
6 I-I - 48 e- → 6 IVII (oxidation)
54 Cl0 + 54 e- → 54 Cl-I (reduction)
2 CrIII - 6 e- → 2 CrVI (oxidation)
CrI3 is a reducing agent, Cl2 is an oxidizing agent, CrI3 is a reducing agent.