Which of the following reactions produces hydrogen?

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

Which set of elements forms stable,covalent,and hydrogen-bonded hydrides?

The correct statements among $(a)$ to $(d)$ are:
$(a)$ Saline hydrides produce $H_2$ gas when reacted with $H_2O$.
$(b)$ Reaction of $LiAlH_4$ with $BF_3$ leads to $B_2H_6$.
$(c)$ $PH_3$ and $CH_4$ are electron-rich and electron-precise hydrides,respectively.
$(d)$ $HF$ and $CH_4$ are called as molecular hydrides.

Which one of the following properties is generally not applicable to ionic hydrides?

Semi-water gas is a mixture of which of the following?