Number of neutrons in a heavy hydrogen atom is

Number of nucleons in $D_2$ molecule is

Ionic hydrides react with water to give:

Identify the correct statements from the following:
$I$. $B_2H_6$ is an electron deficient hydride.
$II$. $NH_3$ is an electron rich hydride.
$III$. $NaH$ is a covalent hydride.
$IV$. $YbH_{2.55}$ is an interstitial hydride.

Which of the following statements is false regarding hydrogen?

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.