1.
On balancing the given redox reaction:
aCr2O72−+bSO32−(aq)+cH+(aq)→2aCr3+(aq)+bSO42−(aq)+H2O(l)a\text{Cr}_2\text{O}_7^{2-} + b\text{SO}_3^{2-}(aq) + c\text{H}^+(aq) \to 2a\text{Cr}^{3+}(aq) + b\text{SO}_4^{2-}(aq) + \text{H}_2\text{O}(l)

The coefficients aa, bb, cc are found to be respectively