24 H2O + 4 KMnO4 + 5 Sb2(SO4)3 → 9 H2SO4 + 2 K2SO4 + 4 MnSO4 + 10 H3SbO4
This is an oxidation-reduction (redox) reaction:
4 MnVII + 20 e- → 4 MnII (reduction)
10 SbIII - 20 e- → 10 SbV (oxidation)
KMnO4 is an oxidizing agent, Sb2(SO4)3 is a reducing agent.