Isotope$(s)$ of hydrogen which emits low energy $\beta^{-}$ particle with $t_{1/2}$ value $> 12 \ years$ is/are :

Consider the following statements about the hydrides: $(I)$ Sodium hydride with water liberates oxygen gas $(II)$ Methane,silane are examples of electron precise hydrides $(III)$ Ammonia and water molecules are examples of electron deficient hydrides $(IV)$ Hydrides of beryllium and magnesium are polymeric in structure. The correct statements are:

What do you understand by $(i)$ electron-deficient,$(ii)$ electron-precise,and $(iii)$ electron-rich compounds of hydrogen? Provide justification with suitable examples.

Pure hydrogen is obtained by carrying out the electrolysis of:

In the following reaction,assign the state for the underlined atom in the product of complete hydrolysis at $R.T.$:
$\underline{B}_2H_6 + H_2O \longrightarrow H_3BO_3 + H_2 \uparrow$

The maximum sum of the number of neutrons and protons in an isotope of hydrogen is