Q.Why is ozone a stronger oxidising agent than dioxygen? Illustrate your answer using the reaction of ozone with potassium iodide solution.

[!TLDR] Ozone decomposes to release oxidising nascent oxygen, making it stronger than O2; it oxidises iodide to iodine in the KI test, which O2 alone cannot do. [!ANSWER] $\text{O}_3 + 2\text{KI} + \text{H}_2\text{O} \rightarrow 2\text{KOH} + \text{I}_2 + \te …

Ozone is a stronger oxidising agent than dioxygen because, unlike the very stable $\text{O}_2$ molecule, ozone is thermodynamically unstable and readily decomposes to release one highly reactive nascent (atomic) oxygen atom alongside stable $\text{O}_2$: $\text{O}_3 \rightarrow \text{O}_2 + [\text{O}]$ This nascent oxygen is a far more aggressive oxidising species than molecular $\text{O}_2$ itself, and it is this nascent oxygen that does the actual oxidising in most of ozone's reactions. The reaction with neutral aqueous potassium iodide illustrates this directly: $\text{O}_3 + 2\text{KI} + \text{H}_2\text{O} \rightarrow 2\text{KOH} + \text{I}_2 + \text{O}_2$ ozone oxidises iodide ion to free iodine (visible as a brown colouration, or as a blue-black colour if starch indicator is present), while being itself reduced back to ordinary oxygen. Crucially, ordinary dioxygen, bubbled through the same neutral KI solution, produces no visible reaction at all under these mild conditions -- it lacks the oxidising power t …

Explain the nascent-oxygen mechanism for ozone's extra oxidising power, then give the KI test equation and state explicitly that O2 …

Omitting the explicit statement that O2 does NOT react with KI (without this contrast, the test does not actually demonstrate ozone's su …