Calcium hydride

File:Calcium Hydride (CaH2).jpg

Calcium hydride powder

Calcium hydride is an inorganic compound with the chemical formula CaH_. It is a gray powder that reacts vigorously with water, releasing hydrogen gas. Calcium hydride is used as a drying agent and as a reducing agent in various chemical reactions.

Chemical Properties

Calcium hydride is a salt-like hydride, composed of calcium and hydrogen. It is a powerful reducing agent and reacts with water to produce calcium hydroxide and hydrogen gas. The reaction can be represented by the following equation:

CaH_ + 2 H_O _ Ca(OH)_ + 2 H__

This property makes calcium hydride useful in generating hydrogen gas in laboratory settings.

Preparation

Calcium hydride can be prepared by the direct combination of calcium and hydrogen at elevated temperatures. The reaction is as follows:

Ca + H_ _ CaH_

This synthesis requires high temperatures and is typically carried out in an inert atmosphere to prevent the formation of calcium oxide.

Applications

Calcium hydride is primarily used as a desiccant for drying solvents and gases. It is also employed in the production of hydrogen gas and as a reducing agent in the synthesis of various organic and inorganic compounds.

Drying Agent

Due to its ability to react with water, calcium hydride is used to dry solvents and gases. It is particularly useful in situations where traditional drying agents, such as molecular sieves, are ineffective.

Hydrogen Generation

Calcium hydride is used in portable hydrogen generators. When mixed with water, it releases hydrogen gas, which can be used as a fuel or in chemical reactions.

Reducing Agent

In organic synthesis, calcium hydride is used to reduce carbonyl compounds to alcohols. It is also used in the reduction of metal oxides to their corresponding metals.

Safety

Calcium hydride is a reactive compound and should be handled with care. It reacts violently with water and acids, releasing flammable hydrogen gas. Proper safety precautions, including the use of gloves and eye protection, should be observed when handling this compound.

Related pages

• Calcium
• Hydrogen
• Reducing agent
• Desiccant