Oxidation-Reduction

Question

Balance the following redox reaction in an acidic solution, using the half-reaction method.

BrO3- (aq)  +  NO2(aq)  🡪  Br-(aq)  +  NO3-(aq)

Answer 1

reduction half reaction:

BrO₃^- ==> Br^-

BrO₃^- ==> Br^- + 3H₂O ... balanced for Br and O

BrO₃^- + 6H⁺ ==> Br^- + 3H₂O ... balanced for Br, O and H using acid (H⁺)

BrO₃^- + 6H⁺ + 6e- ==> Br^- + 3H₂O ... balanced for mass and charge = balanced reduction reaction

oxidation half reaction:

NO₂ ==> NO₃^-

NO₂ + H2O ==> NO₃^- ... balanced for N and O

NO₂ + H₂O ==> NO₃^- + 2H⁺ ... balanced for N, O and H using acid (H⁺)

NO₂ + H₂O ==> NO₃^- + 2H⁺ + 1e- ... balanced for mass and charge = balanced oxidation reaction

To equalize electrons, multiply oxidation reaction by 6 and then add the two equations to get:

BrO₃^- + 6H⁺ + 6e- + 6NO₂ + 6H₂O ==> Br^- + 3H₂O + 6NO₃^- + 12H⁺ + 6e-

Combine/cancel like terms:

BrO₃^- + 6NO₂ + 3H₂O ==> Br^- + 6NO₃^- + 6H⁺ ... BALANCED REDOX EQUATION