18 H2O2 + 2 KMnO4 + 6 H2SO4 → K2S4 + 2 MnSO4 + 18 O2 + 24 H2O
This is an oxidation-reduction (redox) reaction:
2 MnVII + 10 e- → 2 MnII (reduction)
4 SVI + 26 e- → 4 S-1/2 (reduction)
36 O-I - 36 e- → 36 O0 (oxidation)
KMnO4 is an oxidizing agent, H2SO4 is an oxidizing agent, H2O2 is a reducing agent.