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

The hydrides of N, O and F are `NH_(3) , H_(2)O and HF` respectively. On the basis of masses of `NH_(3), H_(2)O` and HF, their boiling points are expected to be lower than the hydrides of the subsequent group members (i.e. `PH_(3), H_(2)S and HCl`) . However, due to high electronegativity of N, O and F, their hydrides undergo extensive intermolecular H-bonding . As a result , the boiling point of `NH_(3), H_(2)O` and HF are much higher than the hydrides of their subsequent group members (i.e., `PH_(3), H_(2)S and HCl`).