*In each of the following equations, indicate the element that has been oxidized and the one that has been reduced and write the corresponding half reactions:
1) 2 Na + FeCl2
à 2
NaCl + Fe
2) 2 PbS + 3 O2
à 2
SO2 + 2 PbO
3) 2 H2
+ O2 à 2
H2O
4) Cu + HNO3
à
CuNO3 + H2
5) AgNO3
+ Cu à
CuNO3 + Ag