The metallic lustre exhibited by sodium is explained by

$A$ chemical $A$ is used for the preparation of washing soda to recover ammonia. When $CO_2$ is bubbled through an aqueous solution of $A$,the solution turns milky. It is used in white washing due to its disinfectant nature. What is the chemical formula of $A$?

Give short explanations on salts of oxo-acids of alkali metal elements.

What happens when : $(i)$ sodium metal is dropped in water? $(ii)$ sodium metal is heated in free supply of air? $(iii)$ sodium peroxide dissolves in water?

What is produced when $Mg$ burns in $CO_2$?

The stability of peroxides and superoxides of alkali metals increases as we go down the group. Explain giving reasons.