Help with half reactions

[fasterthanwoo]

Thanks for the help guys.

 

[Bohrok]

You need equal amounts of the elements O and H on both sides of the equation. Try adding H₂O on the left side and balance the elements, then balance the charges.

 

[fasterthanwoo]

Thanks for the help guys.

 

[symbolipoint]

I am still having some trouble with this.

The MnO4 is being reduced.

The oxidation state of MnO4 is 7. The oxidation state of MnO2 is 4. Therefore I need three e- to reduce?

Is it needed to have H2O on the left side of the reaction?

Thank you.

Yes. Three electrons to reduce Mn. Now balance the electrons for both half-reactions before worrying about the H's and the O's and the H₂O's.

 

[fasterthanwoo]

Thanks for the help guys.