$BeCl_2 + LiAlH_4 \to X + LiCl + AlCl_3$
Total number of $3c-4e^\Theta$ bonds present in the monomer form of compound $(X)$ is:

The hydrides of which group elements of the periodic table form electron-precise hydrides?

On reaction with $Mg$,very dilute nitric acid produces

Identify the hydride which is not correctly matched with the example given in brackets?

Identify the correct statements from the following.
$(i)$ The number of hydrogen bonded water molecules in copper sulphate pentahydrate is one.
$(ii)$ Lanthanum and zirconium form non-stoichiometric hydrides.
$(iii)$ In solid form of $H_2O$, each oxygen is surrounded by six oxygen in octahedral positions at a distance of $276 \ pm$.

In which of the following reactions is dihydrogen not evolved?