What do you expect the nature of hydrides is, if formed by elements of atomic numbers 15,19,23 and 44 with dihydrogen? Compare their behaviour towards water.

Explanation

The element with Z = 15 is non-metal phosphorus and hence it forms the covalent hydride `PH_(3)`.
(2) The element with Z=19 is the alkali metal potassium and hence it forms the saline or ionic hydride `K^(+)H^(-)`.
(3) The element with Z = 23 is the transition metal vanadium of group-3 and hence it forms the interstitial hydride (`VH_(1.6)`).
(4) The element with Z = 44 is the transition metal ruthenium (Ru) belonging to group 8. If does not form any hydride (hydride gap).
Only the ionic hydride, KH reacts with water evolving dihydrogen.
KH(s) + `H_(2)O(l) rarr KOH(aq) + H_(2) (g)`