Peroxide bond is present in

Two litres of $15$ volume solution of $H_2O_2$ on complete decomposition liberated $x$ litres of $O_2$ at $STP$. What is the value of $x$ (in litres)?

Decomposition of $H_2O_2$ is prevented by

The normality of $20$ volume solution of hydrogen peroxide is (in $N$)

The concentration of commercial $H_2O_2$ is $3.125 \ M$,then its grade is $..........$ volume.

What is the $O-O-H$ bond angle in the solid form of $H_2O_2$ (in $^{\circ}$)?