What is Hydrolith? How does it react with water?

Hint :Calcium is an atomic number 20 chemical element with the symbol Ca. Calcium is a reactive alkaline earth metal that produces a black oxide-nitride layer when exposed to air. It shares the same physical and chemical characteristics as its heavier homologues strontium and barium. After iron and aluminium, it is the fifth most plentiful element in the Earth's crust and the third most abundant metal.

Complete Step By Step Answer:
The chemical compound calcium hydride (hydrolith) has the formula $ Ca{H_2} $ and is hence an alkaline earth hydride. This grey powder (white if pure, which is uncommon) interacts quickly with water, releasing hydrogen gas. $ Ca{H_2} $ is therefore employed as a desiccant or drying agent. $ Ca{H_2} $ is a saline hydride, which means it has a salt-like structure. Saline hydrides are formed by alkali metals and alkaline earth metals heavier than beryllium. Sodium hydride, which crystallises in the NaCl pattern, is a well-known example. These substances are insoluble in any solvent that does not react with them. $ Ca{H_2} $ crystallises as $ PbC{l_2} $ (cotunnite) in the $ PbC{l_2} $ structure.
Calcium hydride is made from its constituent components by combining calcium and hydrogen at temperatures ranging from 300 to 400 degrees Celsius. The following is a diagram of the $ Ca{H_2} $ water reaction:
 $ Ca{H_2}\; + {\text{ }}2{\text{ }}{H_2}O{\text{ }} \to {\text{ }}Ca{\left( {OH} \right)_2}\; + {\text{ }}2{\text{ }}{H_2} $
The gaseous $ {H_2}{\text{ \& }}Ca{\left( {OH} \right)_2} $ hydrolysis products are easily separated from the dry solvent.
Calcium hydride is a moderate desiccant that is likely inefficient when compared to molecular sieves. It is less reactive than sodium metal or sodium-potassium alloy and is therefore safer to use. Desiccants for basic solvents such as amines and pyridine are commonly used calcium hydride. It's also used to dry alcoholic beverages.
Calcium hydride is a moderate desiccant that is likely inefficient when compared to molecular sieves. It is less reactive than sodium metal or sodium-potassium alloy and is therefore safer to use. Desiccants for basic solvents such as amines and pyridine are commonly used calcium hydride. It's also used to dry alcoholic beverages.

Note :
'The trade name for this chemical is "hydrolith," and it may be utilised as a portable supply of hydrogen to fill airships in an emergency. It's a bit pricey for this purpose.' The term "emergency" is most likely referring to a situation that occurs during a conflict. However, for decades, the chemical has been routinely used to inflate weather balloons in a safe and easy manner. It's also commonly used in laboratories to make tiny amounts of ultrapure hydrogen for research. The hydrogen produced after treatment with $ Ca{H_2} $ is used to assess the moisture content of diesel fuel.