What is the formula of lithium imide?

What is the molecular formula of lithium tetrahydridoaluminate?

Lithium shows diagonal relationship with

$A$ substance $X$ is a compound of an element of group $IA$. The substance $X$ gives a violet colour in flame test. $X$ is

Which of the following statements about the sulphates of alkali metals is correct?

The white precipitate $(Y)$, obtained on passing a colourless and odourless gas $(X)$ through an ammoniacal solution of $NaCl$, loses about $37 \%$ of its weight on heating and a white residue $(Z)$ of basic nature is left. Identify $(X)$, $(Y)$, and $(Z)$ from the following sets.