Balance the following redox reaction in acidic solution:

Question

Balance the following redox reaction in acidic solution:

I−(aq)+OCl−(aq)⟶Cl−(aq)+I2(aq)

Answer 1

Looking at the half reactions:

I^-(aq) ==> I₂₍aq) must be balanced for mass and charge

2I^-(aq) ==> I₂(aq) + 2e- now balanced for mass and charge

OCl^-(aq) ===> Cl^- must be balanced for mass and charge. Balance for mass first

OCl^-(aq) ===> Cl^- + H₂O This balances the oxygens, but now need H on left side. Since in acid, add H⁺

2H⁺ + OCl^- ===> Cl^- + H₂O This is now balanced for mass. Must now balance charge

2H⁺ + OCl^- + 2e- ===> Cl^- + H₂O This is now balanced for mass and charge

Since both half reactions used 2 electrons, the electrons balance and we can simply add the two balanced half reactions together. Thus, you obtain

2I^-(aq) + OCl^-(aq) + 2H⁺(aq) ===> I₂(aq) + Cl^-(aq) + H₂O(l) This is balanced for both mass and charge