What is formed by the reaction of water with sodium peroxide?

$20$ volume $H_2O_2$ solution has a strength of about $........... \%$

Which of the following cannot be oxidised by $H_2O_2$?

$A$ compound $(MO_2)$ of a group $1$ element $(M)$ is hydrolyzed to form $M^{+}$,$OH^{-}$,$X$,and $Y$. When $X$ reacts with $I_2$ in a basic medium,the products formed are $I^{-}$,water,and $Y$. Then $X$ and $Y$ are respectively:

On reaction with a stronger oxidizing agent like $KIO_{4}$,hydrogen peroxide is oxidized with the evolution of $O_{2}$. The oxidation number of $I$ in $KIO_{4}$ changes to $..........$

The normality of $10$ $V$ (volume) hydrogen peroxide is: