5 KMnO4 + 14 KNO2 + 6 H2SO4 → K5SO4 + 5 MnSO4 + 14 KNO3 + 6 H2O
This is an oxidation-reduction (redox) reaction:
5 MnVII + 25 e- → 5 MnII (reduction)
SVI + 3 e- → SIII (reduction)
14 NIII - 28 e- → 14 NV (oxidation)
KMnO4 is an oxidizing agent, H2SO4 is an oxidizing agent, KNO2 is a reducing agent.