What is produced when sodium nitrate is heated at $800 \, ^oC$?

Caesium is used in

Which of the following compounds is used as a fire extinguisher?

Lithium resembles magnesium in some of its properties. Mention two such properties and give reasons for this resemblance.

$A$ compound $(M_2O_2)$ of group $I$ element $(M)$ hydrolyses to form $M^{+}$,$OH^{-}$ and $X$. Another compound $(M'O_2)$ of group $I$ element $(M')$ hydrolyses to form $(M')^{+}$,$OH^{-}$,$X$ and $Y$. What are $X$ and $Y$ respectively?

$A$ fire of lithium,sodium,and potassium can be extinguished by