Solution:

The components of nuclear numbers 15 is phosphorus, 19 potassium, 23 is vanadium and 44 is ruthenium

Hydride of Phosphorus

Hydride of phosphorus $\left(\mathrm{PH}_{3}\right.$ ) is covalent in nature. Because of the presence of abundance electrons as a solitary pair on Phosphorus, it is electron rich.

Hydride of potassium

Because of high electropositive nature of potassium, the dihydrogen structures ionic hydrides alongside potassium. Normally it is non – unpredictable and translucent.

Hydrides of Vanadium

Vanadium have a place with d-block in occasional table. The metals of d-block structures non-stoichiometric or metallic hydrides. Hydrides of vanadium are normally metallic and have inadequacy of hydrogen.

Hydrides of Ruthenium

Ruthenium has a place with $d$ – block in the occasional table. The metals of $d$ – block structures non-stoichiometric or metallic hydrides. Hydrides of ruthenium are normally metallic and have lack of hydrogen.

Conduct of hydrides towards water

P otassium hydride responds viciously with water as:

$K H_{(s)}+H_{2} O_{(a q)} \rightarrow K O H_{(a q)}+H_{2(g)}$

Smelling salts $\left(\mathrm{NH}_{3}\right)$ acts as a Lewis base and responds with water as:

$H_{2} O_{(l)}+N H_{3(a q)} \rightarrow O H_{(a q)}^{-}+N H_{4(a q)}^{+}$

Hydrides of vanadium and Ruthenium don’t respond with water. Subsequently, the expanding request of reactivity of the hydrides is $(\mathrm{V}, \mathrm{Ru}) \mathrm{H}<\mathrm{PH}_{3}<\mathrm{KH}$.