Hydrolysis of peroxo-disulphuric acid $(H_2S_2O_8)$ gives

$A$ 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.

Which of the following can reduce the decomposition of $H_2O_2$ on exposure to light?

$10 \, mL$ of $H_2O_2$ solution $(d = 1 \, g/mL)$ when reacted with $KI$ solution produced $0.5 \, g$ of iodine. Calculate the percentage purity of $H_2O_2$ .............. $\%$

What is the volume strength of a $3.0 \ N$ $H_2O_2$ solution in liters?

$H_2O_2$ reduces $K_4[Fe(CN)_6]$ in which of the following conditions?