How to balance this manganese peroxide reaction with hydrogen peroxide? [duplicate]








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[Multiple solutions in the balancing of redox reactions](/questions/63369/multiple-solutions-in-the-balancing-of-redox-reactions)

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I have the following equation, already written, with a few coefficients to write.


$\ce{2MnO4^- + a H2O2 + b H+ -> 2Mn^2+ +c O2 + dH2O}$


I have put a = 1, b = 6, c = 3 and d = 4.


The number of atoms and the charges appear balanced to me. It is wrong, so where am I mistaking?


EDIT:**I have just noticed that the exercise says "under acidic conditions": may it help?**




The solution is not unique.


$\ce{2 MnO\_4^- + 1 H\_2O\_2 + 6 H^+}\rightarrow \ce{2 Mn^{2+} + 3 O\_2 + 4 H\_2O}$


And


$\ce{2 MnO\_4^- + 3 H\_2O\_2 + 6 H^+}\rightarrow \ce{2 Mn^{2+} + 4 O\_2 + 6 H\_2O}$


And


$\ce{2 MnO\_4^- + 5 H\_2O\_2 + 6 H^+}\rightarrow \ce{2 Mn^{2+} + 5 O\_2 + 8 H\_2O}$


You really have two reactions:


$\ce{2 MnO4- + 6 H^+ -> 2 Mn^2+ +} \frac 52 \ce{O2 + 3 H2O}$


And


$\ce{H2O2 ->} \frac 12 \ce{O2 + H2O}$


The coefficients you get by adding these together depend on how much permanganate and hydrogen peroxide are assumed to react.


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