Oxygen is not evolved on reaction of ozone with

Which one of the following is most acidic?

Observe the following statements :
$a$. The thermal stability of hydrides of group $16$ elements follows the order :
$H_2O > H_2S > H_2Se > H_2Te$
$b$. Acidic nature of hydrides of group $16$ elements follows the order :
$H_2O < H_2S < H_2Se < H_2Te$
$c$. The reducing nature of $H_2S$,$H_2Se$ and $H_2Te$ follows the order :
$H_2S < H_2Se < H_2Te$
The correct statements are:

Which is the correct thermal stability order for $H_2 E$ $(E = O, S, Se, Te, Po)$?

Peroxymonosulfuric acid is known as ..........

Concentrated $H_2SO_4$ reacts with $PCl_5$ to produce