Which ion can not be oxidised by ozone?

Ozone is known to be a strong oxidizing agent because it releases nascent oxygen which is highly reactive.

• I has -1 oxidation state in ${\mathrm{I}}^{-}$ and can go up to +7 oxidation state. This implies that iodide ion can easily oxidize in the presence of ozone.
• The oxidation state of As in ${\mathrm{AsO}}_3^{3-}$ is +3 and can go up to +5. This implies that it can undergo oxidation in the presence of ozone.
• Fe exists in +3 and +2 oxidation states. Oxidation of Fe in $[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}^{3-}$ is +3. Fe is already presented in its highest oxidation state, therefore it cannot be oxidized in the presence of ozone.
• The oxidation state of Mn in ${\mathrm{MnO}}_4^{2-}$ is +6 and can go up to +7. Therefore, it can undergo oxidation in the presence of ozone.