5 H2 (g) + 2 KMnO4 (aq) + 3 H2SO4 (aq) → 2 MnSO4 (aq) + K2SO4 (aq) + 8 H2O (l)
This is an oxidation-reduction (redox) reaction:
2 MnVII + 10 e- → 2 MnII (reduction)
10 H0 - 10 e- → 10 HI (oxidation)
KMnO4 is an oxidizing agent, H2 is a reducing agent.