1) What was oxidized ? N2H4 + O2 --> N2 + 2H2O
2) Which is NOT an oxidation-reduction equation?
4Fe + 3O2 --> 2Fe2O3
CuO + H2 --> Cu + H2O
2Na + H2 --> 2NaH2
Cu( s) + 2AgCl( aq) --> 2Ag( s) + CuCl2( aq)
2HCl + Ba(OH) 2 --> BaCl2 + 2H2O