Answer:
Two
Explanation:
I believe your unbalanced equation should be
H₂O₂ + I₂ ⟶ IO₃⁻
The half-reactions and the overall reaction are:
5 × [H₂O₂ + 2H⁺ +2e⁻ ⟶ 2H₂O]
1 × [ I₂ + 6H₂O ⟶ 2IO₃⁻ + 12H⁺ + 10e⁻]
5H₂O₂ + I₂ ⟶ 2IO₃⁻ + 2H⁺ + 4H₂O
The reaction needs two hydrogen ions for balancing.
