10 FeCl2 + 8 KMnO4 + 27 H2SO4 → 5 Fe2(SO4)3 + 10 HOCl2 + 8 MnSO4 + 4 K2SO4 + 22 H2O
This is an oxidation-reduction (redox) reaction:
8 MnVII + 40 e- → 8 MnII (reduction)
20 Cl-I - 30 e- → 20 Cl1/2 (oxidation)
10 FeII - 10 e- → 10 FeIII (oxidation)
KMnO4 is an oxidizing agent, FeCl2 is a reducing agent, FeCl2 is a reducing agent.