Solvay's process is used for the preparation of

Alkali metal salts are

The correct order of increasing solubility in water is

Which one of the alkali metals forms only the normal oxide,$M_2O$,on heating in air?

$KO_2 + CO_2 + H_2O \xrightarrow{\text{more } CO_2} [X] + [Y]$
Products $[X]$ and $[Y]$ are respectively

Based on lattice energy and other considerations,which one of the following alkali metal chlorides is expected to have the highest melting point?