Question

MnO4^– + SO3^2– + H2O → MnO2 + SO4^2– + OH^–

If the reaction occurs in an acidic solution where water and H+ ions are added to the half-reactions to balance the overall reaction, how many electrons are transferred in the balanced reduction half-reaction?

The answer I got is 3*2 which equals 6.

Answer 1

Mn goes from +7 to +4 : gained three.
S goes from +4 to +6: lost two
O is unchanged
H is unchanged
so above total is six, once you balance electrons. (2Mn, 3S)

Answer 2

Howefer, I'm having trouble with this problem because in an acidic solution KMnO4 goes to Mn^2+ and not MnO2.

Answer 3

I noticed that as well, Dr. Bob. I'm not quite sure why my teacher has it set up this way.

Answer 4

Thank you for clearing this up. So it isn't a typo. I suspect your teacher just goofed with the problem. As it stands, however, it isn't possible to answer the question becasue the question is flawed..