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.

(D) $1$. False: Metals of group $7$,$8$ and $9$ do not form hydrides at all. This region of the periodic table is known as the hydride gap.
$2$. False: This process produces syngas $(CO + H_2)$,not pure dihydrogen. Pure dihydrogen is obtained by the electrolysis of acidified water or other specific methods.
$3$. True: Hydrogen has a very high ionization enthalpy $(1312 \ kJ \ mol^{-1})$ compared to alkali metals due to its small size and the proximity of the electron to the nucleus.
$4$. True: Hydrogen shows metallic character by forming $H^+$ ions and non-metallic character by forming $H^-$ ions or covalent bonds.