Question

Why does $O_3$ act as a powerful oxidising agent?

Answer 1

Oxidising nature of $O_3$

On heating, $O_3$ readily decomposes to give $O_2$ and nascent oxygen.

$O_3\to O_2+O$
nascent oxygen
Sincenascent oxygen is very reactive, therefore, $O_3$ acts as a powerful oxidising agent.
For example, it oxidises lead sulphide to lead sulphate and iodide ions to iodine.

$PbS\left(s\right)+4O_3\left(g\right)\to PbS{O}_4\left(s\right)+4O_2\left(g\right)$

$2I^{-}\left(aq\right)+H_{2}O\left(l\right)+O_3\left(g\right)\to 2O{H}^{-}\left(aq\right)+I_2\left(s\right)+O_2\left(g\right)$