Carnallite does not contain

Sodium carbonate is manufactured by the Solvay process. The products that are recycled are:

Observe the following statements:
Statement-$I$: Both $LiF$ and $CsI$ have low solubility in water.
Statement-$II$: Low solubility of $LiF$ in water is due to its high lattice enthalpy, and that of $CsI$ is due to its smaller hydration enthalpy of ions.

Which alkali metal emits blue colour light in a flame test?

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

Identify the $CORRECT$ decreasing order of melting point of cluster of sodium atoms depending on size.