a. Would you except the hydrides of `N,O` and `F` to have lower boiling points than the hydrides of their subsequent group members? Give reason.
b. Can phosphorous with outer electronic configuration `3s^(2)3p^(3)` form `PH_(5)`?
c. How many hydrogen-bonded water molecules(s) are associated with `CuSO_(4).5H_(2)O`?

Explanation

On the basis of molecular masses of `NH_2, H_2O and HF`, their boiling points are expected to be lower than those of the next 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 of `NH_3, H_2O and HF` will be higher than the hydrides of their next group member.