J.R. S. answered 11/28/22
Ph.D. University Professor with 10+ years Tutoring Experience
MnO₄⁻(aq) + S₂O₃²⁻(aq) → S₄O₆²⁻(aq) + Mn²⁺(aq) ... unbalanced equation
MnO4- ==> Mn2+ ... unbalanced reduction half reaction (Mn goes from +7 to +2)
MnO4- ==> Mn2+ + 4H2O .. balanced for Mn and O
MnO4- + 8H+ ==> Mn2+ + 4H2O .. balanced for Mn, O and H (using acid, H+)
MnO4- + 8H+ + 5e- ==> Mn2+ + 4H2O .. balanced for Mn, O, H and charge = BALANCED HALF REACTION
S2O32- ==> S4O62- .. unbalanced oxidation half reaction (S goes from +2 to +2.5)
2S2O32- ==> S4O62- .. balanced for S and O
2S2O32- ==> S4O62- + 2e- .. balanced for S, O and charge = BALANCED HALF REACTION
Multiply reduction half reaction by 2 and oxidation half reaction by 5 to equalize electrons:
2MnO4- + 16H+ + 10e- ==> 2Mn2+ + 8H2O
10S2O32- ==> 5S4O62- + 10e-
Add together and combine/cancel like terms to get final balanced redox equation:
2MnO4- + 16H+ + 10S2O32- ==> 2Mn2+ + 8H2O + 5S4O62- ... BALANCED REDOX EQUATION