The number of neutrons in tritium is

Dihydrogen of high purity $(>99.95 \%)$ is obtained through:

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

Which property of hydrogen distinguishes it from alkali metals?

State True or False for the following statements:
$1$. Metals of group $7$,$8$ and $9$ form non-stoichiometric hydrides.
$2$. Pure dihydrogen is obtained by heating hydrocarbons with $H_2O$ vapour in the presence of a $Ni$ catalyst at $1270 \ K$.
$3$. The ionization enthalpy of hydrogen is higher than that of alkali metals.
$4$. Some chemical properties of hydrogen resemble both metals and non-metals.

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