Identify the electron-rich hydrides from the following.

Which of the following is used as a promoter in the Bosch process?

What do you understand by the term non-stoichiometric hydrides? Do you expect this type of hydrides to be formed by alkali metals? Justify your answer.

Which of the following is an electron-precise type of hydride?

Arrange the following:
$(i)$ $CaH_2$,$BeH_2$ and $TiH_2$ in order of increasing electrical conductance.
$(ii)$ $LiH$,$NaH$ and $CsH$ in order of increasing ionic character.
$(iii)$ $H-H$,$D-D$ and $F-F$ in order of increasing bond dissociation enthalpy.
$(iv)$ $NaH$,$MgH_2$ and $H_2O$ in order of increasing reducing property.

Which of the following cannot be used for the preparation of $H_2$?