What is the structural formula of lithium tetrahydridoaluminate?

Which of the following statements is not true for hydrogen:
$1)$ It exists as a diatomic molecule.
$2)$ It has one electron in the outermost shell.
$3)$ It can lose an electron to form a cation which can freely exist.
$4)$ It cannot form ionic compounds.

In the manufacture of hydrogen from water gas $(CO + H_2)$,which of the following is the correct statement?

Ionisation of $H$-atom would produce

Which of the following combinations represents water gas?

Among the following reactions of hydrogen with halogens,the one that requires a catalyst is