Which of the following cannot be oxidized by ozone gas $(O_3)$?

Which of the following oxides cannot act as a reducing agent?

Which of the following cannot function as an oxidising agent?

$HNO_2$ acts both as a reductant and an oxidant,while $HNO_3$ acts only as an oxidant. This is due to their:

Identify the change in the oxidation state of the oxidising agent in the following redox reaction: $3H_3AsO_3(aq) + BrO_3^-(aq) \rightarrow Br^-(aq) + 3H_3AsO_4(aq)$

In the reaction $Cr_2O_7^{2-} + X \xrightarrow{H^+} Cr^{3+} + H_2O + \text{Oxidized product of } X$,which of the following cannot be $X$?