2 FeIICl2 + H2O2-I + 2 HCl 2 FeIIICl3 + 2 H2O-II

This is an oxidation-reduction (redox) reaction:

2 FeII - 2 e- 2 FeIII (oxidation)

2 O-I + 2 e- 2 O-II (reduction)

Change the oxidation states