Which of the following is not a peroxide?

Rohan heard that instructions were given to the laboratory attendant to store a particular chemical,i.e.,keep it in the dark room,add some urea in it,and keep it away from dust. This chemical acts as an oxidising as well as a reducing agent in both acidic and alkaline media. This chemical is important for use in the pollution control treatment of domestic and industrial effluents.
$(i)$ Write the name of this compound.
$(ii)$ Explain why such precautions are taken for storing this chemical.

The volume strength (in $L$) of $3$ $N$ $H_2O_2$ is approximately

The correct statements among the following are
$i$. Saline hydrides produce $H_2$ gas when reacted with water
$ii$. Presently $\sim 77 \%$ of the industrial dihydrogen is produced from coal
$iii$. Commercially marketed $H_2O_2$ contains $3 \% H_2O_2$

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 :

The substance used as a bleaching agent for washing clothes is .....