Blackened oil painting can be restored into original form by the action of :

The normality of $30$ volume $H_2O_2$ is (in $N$)

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)

When $CO_2$ is bubbled through a solution of barium peroxide in water:

The volume of oxygen liberated from $15 \, mL$ of $20$ volume $H_2O_2$ is ................ $mL$.

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