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 $..........$

$25$ volume hydrogen peroxide means

Which of the following equations depicts the oxidizing nature of $H_{2}O_{2}$?

Perhydrol is an aqueous solution of

The volume strength of $8.9 \, M \, H_{2}O_{2}$ solution calculated at $273 \, K$ and $1 \, atm$ is.........
$(R = 0.0821 \, L \, atm \, K^{-1} \, mol^{-1})$ (rounded off to the nearest integer)

The correct statements from the following are:
$i$. $Ca(OH)_2$ is used in Clark's method of removal of temporary hardness of water.
$ii$. $100 \ mL$ of $10$ vol $H_2O_2$ on complete decomposition liberates $1 \ L$ of oxygen at $STP$.
$iii$. Urea can be added to the solution of $H_2O_2$ as stabilizer.