Name the classes of hydrides to which $H_2O$,$B_2H_6$ and $NaH$ belong.

Which one of the following is the most abundant element in the universe?

In the manufacture of hydrogen from water gas $(CO + H_2)$,which of the following is the correct statement?

In the Bosch process,which of the following gases is used for the production of $H_2$ gas?

Metals of groups $7$,$8$,and $9$ do not form metallic hydrides. This is termed as

Lithium hydride can be used to prepare other useful hydrides. Beryllium hydride is one of them. Suggest a route for the preparation of beryllium hydride starting from lithium hydride. Write chemical equations involved in the process.