Which two of the following chemical equations are properly balanced?

1. C2H4 3 O2 2 CO2 2 H2O

2. Fe2O3 2 C 2 Fe 3 CO2

3. Pb(NO3)2(aq) NaCl(aq) NaNO3(aq) PbCl2(s)

4. 3 H2 2 N2 2 NH3

5. NaHCO3 HCl CO2 H2O NaCl