Electrolysis of Fused Calcium Hydride

The electrolysis of fused calcium hydride involves the decomposition of the compound into its constituent elements, calcium and hydrogen. During this process, a direct electric current is passed through the molten calcium hydride, which causes the positive and negative ions to migrate towards the respective electrodes.

1. Cathode
The cathode is the electrode connected to the negative terminal of the power supply. It attracts positively charged ions, known as cations, present in the molten calcium hydride. In this case, calcium ions (Ca2+) would be attracted to the cathode. However, since calcium is less reactive than hydrogen, it is the hydrogen ions that actually get reduced at the cathode.

2. Anode
The anode is the electrode connected to the positive terminal of the power supply. It attracts negatively charged ions, known as anions, present in the molten calcium hydride. In this case, hydride ions (H-) would be attracted to the anode. However, the hydride ions are highly reactive and readily undergo oxidation to produce hydrogen gas. Therefore, the hydrogen gas is liberated at the anode.

3. Hydrogen Liberation
Since the cathode attracts hydrogen ions (H+), it might seem that hydrogen gas would be liberated at the cathode. However, due to the high reactivity of the hydride ions, they undergo oxidation at the anode to produce hydrogen gas. Therefore, no hydrogen liberation occurs at the cathode.

4. Reaction with Oxygen
The hydrogen gas produced at the anode reacts with any available oxygen present in the surrounding environment. This reaction involves the combination of hydrogen gas (H2) with oxygen gas (O2) to form water (H2O). The reaction is highly exothermic, releasing a significant amount of heat energy.

2H2(g) + O2(g) → 2H2O(g)

The liberation of hydrogen gas at the anode and its subsequent reaction with oxygen to form water are important aspects of the electrolysis process. These reactions occur simultaneously as a result of passing an electric current through the fused calcium hydride, leading to the decomposition of the compound and the formation of water.

Anode. Because during electrolysis cah2 dissociate in ca2+ and h- . And in electrolysis negative ion moves towards anode which is positive in nature in case of electrolysis