Thread: redox equation

I'm kind of self studying for this topic so i need some help.

Write a fully balanced redox equation for the reaction that occurs when sulfur dioxide gas is bubbled through an acidified solution of potassium permanganate.

The book has this answer:
(2MnO4 -) + (5SO2) + (2H2O) + (6H +) = (5SO4 2-) + (2Mn 2+)

I got this answer:
(2MnO4 -) + (5SO2) + (2H2O) = (5SO4 2-) + (4H +) + (2Mn 2+)

I didn't bother typing the working as it gets tedious. I just want to know which answer is correct.

Originally Posted by chocolate123

I'm kind of self studying for this topic so i need some help.

Write a fully balanced redox equation for the reaction that occurs when sulfur dioxide gas is bubbled through an acidified solution of potassium permanganate.

The book has this answer:
(2MnO4 -) + (5SO2) + (2H2O) + (6H +) = (5SO4 2-) + (2Mn 2+)

I got this answer:
(2MnO4 -) + (5SO2) + (2H2O) = (5SO4 2-) + (4H +) + (2Mn 2+)

I didn't bother typing the working as it gets tedious. I just want to know which answer is correct.

Your answer seems to be correct.

There are 2 problems with the book answer:
1. The charges aren't balanced.
2. The H+'s are on the wrong side; this makes the equation unbalanced (there is no Hydrogen on the right).

Edit: Isn't school out? Or are you preparing for AP Chem next year?

Ok thanks.
We will learn redox a bit later on in the year at school. But because my chemistry teacher is new - has never taught chemistry or any high school students before, I don't think I can rely on him completely, so i just decided to study a little myself.

arnt your charges unbalanced also?

I think the right answer could be:

5SO2 + 2MnO4(-) <-> 5S04(2-) + 2Mn(2+) + 4H(+)

or, if you prefer it complete,

5S02 + H2O + 2 KMnO4 <-> K2SO4 + 2H2SO4 + 2MnSO4

Best regards,

César