18 KI + 2 KMnO4 + 12 H2SO4 → 2 MnSO2 + 9 I2 + 10 K2SO4 + 12 H2O
This is an oxidation-reduction (redox) reaction:
2 MnVII + 10 e- → 2 MnII (reduction)
2 SVI + 8 e- → 2 SII (reduction)
18 I-I - 18 e- → 18 I0 (oxidation)
KMnO4 is an oxidizing agent, H2SO4 is an oxidizing agent, KI is a reducing agent.