Which metal oxide among the following gives $H_2O_2$ on treatment with dilute acid?

Which of the following gives $H_2O_2$ on hydrolysis?

How does $H_2O_2$ behave as a bleaching agent?

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

Decomposition of $H_2O_2$ is prevented by