Balance the following reactions:
Pb(s) + PbO2(s) + H2SO4 --> PbSO4(s)
H3AsO4 + Zn(s) --> As + Zn^+2
O3 + NO --> O2 + NO2
This question is like a reverse disproportionation reaction. You must first divide it into 2 half reactions. For a simplification, ignore the anion associated with the acid. The next thing to do is to add the two reactions together in such a way as to eliminate electrons. Now we can in the acid anions to both sides to balance out.