Answer
$H_{2}O_{2} (aq) + 2ClO_{2} (aq) +2OH^{-} (aq) → 2ClO_{2}^{-} (aq) + O_{2} (g) + 2H_{2}O$
Oxidizing Agent: $ClO_{2}$
Reducing agent: $H_{2}O_{2}$
Work Step by Step
We add OH- to left side and water to right hand side to balance the equation as it is in basic medium. Oxidation state of Cl is changed from +4 to +3, hence it is reduced and state of O is changed from -2 to 0, hence it is oxidized.