5 C4H6 (g) + 22 KMnO4 (aq) + 33 H2SO4 (aq) → 22 MnSO4 (aq) + 11 K2SO4 (aq) + 20 CO2 (g) + 48 H2O (l)
This is an oxidation-reduction (redox) reaction:
22 MnVII + 110 e- → 22 MnII (reduction)
20 C-3/2 - 110 e- → 20 CIV (oxidation)
KMnO4 is an oxidizing agent, C4H6 is a reducing agent.