0 0 +2 -2
2Zn + O2 = 2ZnO
-2e +2e*2
0 +1 +2 0
Zn + 2HCl = ZnCl2 + H2
-2e +e
0 0 +2 -1
Zn + Cl2 = ZnCl2
-2e +e*2
0 +1 +2 0
Zn+H2SO4 = ZnSO4 + H2
-2e +e
0 0 +3 -2
2Al + 3O2 = 2Al2O3
-3e +2e*2
0 -1 +3 -1
Al + Cl2 = 2AlCl3
-3e +e*2
0 +1 +3 0
Al + HCl = AlCl3 + H2
-3e +e
0 +1 +3 0
2Al + 3H2SO4 = Al2(SO4)3 + 3H2
-3e +e