Which of the following elements release $H_2$ gas on reaction with $NaOH$?

Starting with sodium chloride,how would you proceed to prepare:
$(i)$ sodium metal
$(ii)$ sodium hydroxide
$(iii)$ sodium peroxide
$(iv)$ sodium carbonate?

The oxide of potassium that does not exist is

Given below are two statements:
Statement $I$: The chlorides of $Be$ and $Al$ have $Cl^{-}$-bridged structure. Both are soluble in organic solvents and act as Lewis acids.
Statement $II$: Hydroxides of $Be$ and $Al$ dissolve in excess alkali to give beryllate and aluminate ions.
In the light of the above statements,choose the correct answer from the options given below.

Among the statements $(a)-(d)$ the correct ones are
$(a)$ Lithium has the highest hydration enthalpy among the alkali metals.
$(b)$ Lithium chloride is insoluble in pyridine.
$(c)$ Lithium cannot form ethynide upon its reaction with ethyne.
$(d)$ Both lithium and magnesium react slowly with $H_2O$.

Which pair of elements on combustion in air give superoxides?