Q.Why does O3 act as a powerful oxidising agent?

Step 1 — Decomposition of ozone.

Ozone is thermodynamically unstable relative to $O_2$ and readily decomposes:

releasing "nascent" (freshly generated, highly reactive) atomic oxygen.

Step 2 — Reactivity of nascent oxygen.

This nascent oxygen atom is far more reactive than molecular $O_2$ because it is not bonded/stabilised, and it readily oxidises other substances (e.g. it turns moist starch-iodide paper blue-black by liberating $I_2$ from KI).

Step 3 — Thermodynamic basis.

$O_3 + 2H^+ + 2e^- \rightarrow O_2 + H_2O, \quad E^\circ = +2.07\ V$ …

Explain ozone's instability/decomposition to nascent oxygen as the chemical mechanism, and cite its high standard reduction potenti …

• Don't just say "ozone is unstable" without connecting it to the release of nascent (atomic) oxygen, which is the actual oxidising species. …