Cr2O3 + 4 NaCO3 + NaNO3 → 2 Na2CrO4 + NaNO2 + 4 CO2
This is an oxidation-reduction (redox) reaction:
4 CV + 4 e- → 4 CIV (reduction)
NV + 2 e- → NIII (reduction)
2 CrIII - 6 e- → 2 CrVI (oxidation)
NaCO3 is an oxidizing agent, NaNO3 is an oxidizing agent, Cr2O3 is a reducing agent.
Warning: Unknown compound 'NaCO3'. Did you mean NaCo3?