What is the oxidation number of $O$ in $H_2O_2$?

Which of the following can produce $H_2O_2$?

Which one of the following chemical agents is not used for the dry-cleaning of clothes?

$1 \ mL$ of "$x$ volume" $H_2O_2$ solution on heating gives $20 \ mL$ of oxygen gas at $STP$. The $(w/v) \%$ corresponding to "$x$ volume" of $H_2O_2$ is

Electrolysis of $X$ gives $Y$ at anode. Vacuum distillation of $Y$ gives $H_2O_2$. The number of peroxy $(O-O)$ bonds present in $X$ and $Y$ respectively are :

Which of the following statements is incorrect?