18 H2SO4 (aq) + 12 KMnO4 (aq) + 5 C2H4 (g) → 28 H2O (l) + 10 CO2 (g) + 6 K2SO4 (aq) + 12 MnSO4 (aq)
This is an oxidation-reduction (redox) reaction:
12 MnVII + 60 e- → 12 MnII (reduction)
10 C-II - 60 e- → 10 CIV (oxidation)
KMnO4 is an oxidizing agent, C2H4 is a reducing agent.