Sorry to resurrect an old forum post, however, just for future reference, I did this question a few days ago and I found that for the second and third reactions you needed to balance these using the half-reaction method (which doesn't make a whole lot of sense because the Zumdahl textbooks only cover this for Electrochemistry later on). Anyway, in doing so you would get the equations:
2MnO
4-(aq) + 16H
+(aq) + 5C
2O
42-(aq) 2Mn
2+(aq) + 8H
2O
(l) + 10CO
2 (g)2MnO
4-(aq) + OH
-(aq) + 3CHO
2-(aq) 3CO
32-(aq) + 2H
2O
(l) + 2MnO
2 (s)The first reaction occurs in acidic solution (because of the sulfuric acid), and the second reaction occurs in basic solution (because of the hydrolysis of water by the formate ion).
KungKemi