Question

A molten ionic hydride on electrolysis gives-

• A. $H^{+}$ ions moving toward the cathode
• B. $H^{+}$ ion moving towards the anode
• C. $H_2$ is liberated at anode
• D. $H_2$ is liberated at cathode

Answer 1

The correct option is C $H_2$ is liberated at anode

Ionic hydrides are formed when hydrogen molecule reacts with highly electropositive s-block elements. These hydride in liquid state gives negatively charged $H^{-}$ ions. In electrolysis oxidation reactions take place at anode. When ionic hydrides are electrolysed, the $H^{-}$ ions moves toward anode and get oxidised at anode to liberates hydrogen gas at anode.

Saline/ionic hydrides :

1. Non-volatile, Non-conducting, Crystalline solids.

2. Most of the s-block metals form this type of hydrides

3. These ionic hydrides have rock-salt structure

4. Significant covalent character found in lighter metal hydrides.

5. Examples: $LiH,NaH,KH,Be{H}_2,Mg{H}_2$

6. $Be{H}_{2}andMg{H}_2$ have covalent polymeric structure