On the basis of molecular masses of `NH_(3), H_(2)O and HF`, their boiling points are expected to be lower than those of the subsequent group member hydrides. However, due to higher electronegativity of N, O and F, the magnitude of hydrogen bonding in their hydrides will be quite appreciable. Hence, the boiling points `NH_(3), H_(2)O and HF` will be higher than the hydrides of t