Explain the following with suitable examples :
Ionic hydrides

Explanation

Ionic hydrides: These are formed by the highly electropositive s-block metals. In s-block metal hydrides LiH, `BeH_(2)` and `MgH_(2)` have some covalent character. The ionic hydrides are cyrstalline.They are non volatile compounds. They are non conducting in solid state. But in molten condition, if electrolysed they give metal at cathode and hydroge at anode.
`CaH_(2)overset("electrolysis")(to)Ca+H_(2)`
This reaction confirms that ionic hydrides contain `H^(-)` ion.
Ionic hydrides liberate hydrogen forming alkaline solution when dissolved in water.
`NaH+H_(2)OtoNaOH+H_(2)`
So Ionic hydrides are used as a source of hydrogen.