Question

Use half equations to balance this equation.

ClO3-(aq)    +    Cl-(aq)     →     Cl2(g)

What is the oxidation state of Cl in the above polyatomic ion?

Answer 1

ClO₃^- (aq) + Cl^- $\to$ Cl₂ (g)

now start balance by half reactions

2ClO₃^- + 12H⁺ + 10e^- $\to$ Cl₂ + 6H₂O

2Cl^- $\to$ Cl₂ + 2e^- now multiply by 5

10Cl^- $\to$ 5Cl₂ + 10e^-

2ClO₃^- (aq) + 12H⁺ + 10Cl^- $\to$ 6Cl₂ + 6H₂O