BALANCING REDOX doubt

sir why are we looking to balance only Na
although your answer is right

if we use 2Na₂SO₄ then S will be unbalanced

for 1st , after writing step 2 ,

u shud write the respective compounds of the species that are in step 2 only ,
for 3S⁶⁺ & 2Cr³⁺ , as they are in the same compound, u shud write that compound only ,bcz if u would hav written Na₂SO₄ , then while balancing Na atoms, u will be adding Na₂CrO₄ , but since Cr is already balanced , u shud not do that .
so
3SO₂ + 2Na₂CrO₄ → Cr₂(SO₄)₃

now balance Na atoms

3SO₂ + 2Na₂CrO₄ → 2Na₂SO₄ + Cr₂(SO₄)₃

now using H₂SO₄ balance SO₄ grp of 2Na₂SO₄ only bcz u already balanced sulphur atoms of Cr₂(SO₄)₃ while balancing with e^-

so
3SO₂ + 2Na₂CrO₄ + 2 H₂SO₄ → 2Na₂SO₄ + Cr₂(SO₄)₃

balance H now and check if O atoms are also getting balanced simultaneously

3SO₂ + 2Na₂CrO₄ + 2 H₂SO₄ → 2Na₂SO₄ + Cr₂(SO₄)₃ + 2H₂O