Question

What are hydrides?

Answer 1

Hint: In simple terms we can define hydride as the anion of hydrogen. As we know that it is a chemical compound where the hydrogen atoms exhibit basic, nucleophilic or reducing properties. Generally in a hydride, the oxidation number of hydrogen is −1. So in this question we have to explain about hydrides.

Complete answer:
Let us begin with the discussion of hydrides followed by its types:-
-Hydrides: These are the compounds of hydrogen with less electronegative elements which means when hydrogen reacts with any other element that is very less electronegative in nature, the product formed is considered to be a hydride.
-Hydrogen molecules generally react with many elements except for noble gases to form hydrides. However, the properties can vary based on the type of intermolecular force existing between the elements, their molecular masses, temperature, and other factors.
-Types of hydrides: These are mainly divided into three categories based on what elements the hydrogen forms bonds with or simply on the basis of chemical bonding and these three categories are explained as follows:-
(A) Ionic Hydrides: These are formed when hydrogen molecules react with highly electropositive s-block elements that are alkali and alkaline earth metals. For example: NaH, CaH, $Ca{{H}_{2}}$, etc. In solid state they are non- conducting and non-volatile whereas in liquid state, they conduct electricity.
(B) Covalent Hydrides: These are formed when hydrogen reacts with other elements that have similar electronegativity like Si, C, etc. For example: $C{{H}_{4}},N{{H}_{3}}$etc. These compounds have covalent bonds and can be volatile as well as non-volatile.
(C) Metallic Hydrides: A hydrogen compound which forms a bond with another metal element is categorized as a metal hydride. These are usually formed with transition metals and are mostly hard with high melting and boiling points. For example: Cadmium hydride, magnesium hydride etc. They do conduct electricity.

Note:
-Hydrides are used as reducing agents in many chemical industries and are highly significant in battery storage technologies for example nickel hydride batteries. They are also used as drying agents and as strong bases in organic synthesis.