Observe the following statements
I. HCN, C2H2 and O2 have multiple bonds
II. N2H4, C2H6 and NH3 does not have multiple bonds
III. NH+14, H3O+ and Ni(CO)4 have co - ordinate covalent bonds
IV. K4[Fe(CN)6] and [Ag(NH3)2]Cl have ionic, covalent and dative bonds
The correct statements are
I, II, III & IV only