The main oxides formed on combustion of $Li, Na$ and $K$ in excess of air are,respectively:

What is the correct order of stability for the superoxides?

Statement $A$: Extraction of magnesium is done by the electrolysis of a molten mixture of $MgCl_2$,$NaCl$,and $CaCl_2$.
Reason $R$: Calcium chloride acts as a reducing agent.

Which of the following metal produces $N_2O$ on reaction with $20\%\ HNO_3$?

Give the uses of alkali metal elements (group-$I$).

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The alkali metals and their salts impart characteristic colour to reducing flame.
Reason $R$: Alkali metals can be detected using flame tests.
In the light of the above statements,choose the most appropriate answer from the options given below.