Molecular weight of KNO2=85 g/mol
Molecular weight of Na2CrO4=162 g/mol
Cr2O3+Na2CO3+KNO3⟶Na2CrO4+CO2+KNO2
Here species which are undergoing change in oxidation number are Cr and N.
Oxidation half:+3Cr2O3→+6CrO2−4 ...(i)
Eq wt of Na2CrO4=1623 g/eq
Reduction half:+5NO−3→+3NO−2 ...(ii)
Eq wt of KNO2=852 g/eq
Sum of eq wt: 54+42.5=96.5 g/eq