Identify the electron-rich hydrides from the following.

Calcium imide on hydrolysis gives gas $(B)$ which on oxidation by bleaching powder gives gas $(C)$. Gas $(C)$ on reaction with magnesium gives compound $(D)$ which on hydrolysis again gives gas $(B)$. Identify $(B)$,$(C)$ and $(D)$.

Which of the following is expected to be high for a proton $(H^+)$?

An alkali metal hydride $(NaH)$ reacts with diborane in '$A$' to give a tetrahedral compound '$B$' which is extensively used as a reducing agent in organic synthesis. The compounds '$A$' and '$B$' respectively are

Liquid ammonia is used in refrigeration because of its

The highest industrial consumption of molecular hydrogen is to produce compounds of element ...... .