Which of the following compounds is a peroxide?

Which of the following can be used to prevent the decomposition of $H_{2}O_{2}$?

In $H_2O_2$ molecule,the dihedral angle between the two $O-H$ planes is ............. $^o$.

What is the approximate volume (in $mL$) of $10$ vol $H_2O_2$ solution that will react completely with $1 \ L$ of $0.02 \ M \ KMnO_4$ solution in acidic medium?

Complete the following chemical reactions.
$i$. $PbS_{(s)} + H_2O_{2_{(aq)}} \rightarrow$
$ii$. $MnO_{4_{(aq)}}^{-} + H_2O_{2_{(aq)}} \rightarrow$
$iii$. $CaO_{(s)} + H_2O_{(g)} \rightarrow$
$iv$. $AlCl_{3_{(s)}} + H_2O_{(l)} \rightarrow$
$v$. $Ca_3N_{2_{(s)}} + H_2O_{(l)} \rightarrow$
Classify the above into $a$. hydrolysis,$b$. redox,and $c$. hydration reactions.

$A$ colourless liquid $A$ contains $H$ and $O$ elements only. It decomposes slowly on exposure to light. It is stabilised by mixing urea to store in the presence of light.
$(i)$ Suggest the possible structure of $A$.
$(ii)$ Write the chemical equation for its decomposition reaction in light.