The correct option is B Cl2+IO−3+2OH−⟶IO−4+2Cl−+H2O
The unbalanced redox equation is as follows:
Cl2+IO−3+OH−⟶IO−4+Cl−
Balance all atoms other than H and O.
Cl2+IO−3+OH−⟶IO−4+2Cl−
The oxidation number of Cl changes from 0 to -1. The change in the oxidation number of Cl per atom is 1. Total change in the oxidation number for 2 Cl atoms is 2.
The oxidation number of I changes from 5 to 7. The change in the oxidation number of iodine is 2.
The increase in the oxidation number is balanced with a decrease in the oxidation number.
O atoms are balanced.
To balance H atoms, add one water molecule on RHS and one hydroxide ion on LHS.
Cl2+IO−3+2OH−⟶IO−4+2Cl−+H2O
This is the balanced chemical equation.