The environmentally friendly chemical used nowadays for bleaching paper in the presence of a suitable catalyst is

Which of the following compounds is a peroxide?

In which of the following reactions does $H_2O_2$ act as an oxidising agent (either in acidic,alkaline,or neutral medium)?
$(i)$ $2Fe^{2+} + H_2O_2 \rightarrow$
$(ii)$ $2MnO_4^{-} + 6H^{+} + 5H_2O_2 \rightarrow$
$(iii)$ $I_2 + H_2O_2 + 2OH^{-} \rightarrow$
$(iv)$ $Mn^{2+} + H_2O_2 \rightarrow$

The structure of $H_2O_2$ is

Assertion $:$ Amount of $H_2O_2$ in a sample can be determined by treating $H_2O_2$ solution with $KI$ and followed by titration of liberated $I_2$ with sodium thiosulphate.
Reason $:$ In this titration,an intense blue colour appears which disappears at the end point.

Which one of the following reactions represents the oxidising property of $H_2O_2$?