4 KNO3 + Cr2(SO4)3 + 4 Na2CO3 → 4 KNO2 + 2 NaCrO4 + 3 Na2SO4 + 4 CO2
This is an oxidation-reduction (redox) reaction:
4 NV + 8 e- → 4 NIII (reduction)
2 CrIII - 8 e- → 2 CrVII (oxidation)
KNO3 is an oxidizing agent, Cr2(SO4)3 is a reducing agent.
Warning: Unknown compound 'NaCrO4'