Which of the following compounds is formed when sodium burns in excess supply of air?

The compound$(s)$ formed upon combustion of sodium metal in excess air is(are):

Sodium hydroxide is produced on a large scale:

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 $MF > MCl > MBr > MI$.

Which of the following is the strongest reducing agent?

Carnallite in water dissociates to give $.....$ ions.