1)5H2SO4+4Zn=H2S+4ZnSO4+4H2O
Zn-2e=Zn+2 4
S+6 +8e=S-2 1
2)2AgNO3+2NaOH=Ag2O+2NaNO3+H2O
3)H2S+PbO=PbS+H20
4)Cu+4HNO3=Cu(NO3)2+2NO2+2H20
Cu0-2e=Cu+2 1
N+5 +1e=N+4 2
1)5H2SO4+4Zn=H2S+4ZnSO4+4H2O
Zn-2e=Zn+2 4
S+6 +8e=S-2 1
2)2AgNO3+2NaOH=Ag2O+2NaNO3+H2O
3)H2S+PbO=PbS+H20
4)Cu+4HNO3=Cu(NO3)2+2NO2+2H20
Cu0-2e=Cu+2 1
N+5 +1e=N+4 2