The word 'alkali' used for alkali metals indicates:

Which among the following elements develops noble gas configuration in $+1$ state?

What is the chemical formula of washing soda?

Carnallite does not contain

Assertion $(A)$: $K$, $Rb$, and $Cs$ form superoxides.
Reason $(R)$: The stability of the superoxides increases from $K$ to $Cs$ due to the decrease in lattice energy.
The correct answer is:

The correct statements are:
$I$. The low solubility of $LiF$ is due to its high lattice enthalpy.
$II$. $LiBr$ is soluble in acetone.
$III$. $LiCl$ is soluble in pyridine.
$IV$. The order of melting points of alkali metal halides is $MF > MCl > MBr > MI$.