Final answer:
O₂ is the oxidizing agent in the reaction because it gains electrons and facilitates the oxidation of C8H7ON, causing the latter to lose electrons.
Step-by-step explanation:
In the reaction given, which is 2C8H7ON + O₂ → C16H10N2O2 + 2H2O, the oxidizing agent is the species that is accepting electrons, which is usually the substance being reduced. In this case, O₂ is gaining electrons and is being reduced to H2O when C8H7ON is oxidized to C16H10N2O2. Therefore, O₂ is the oxidizing agent.
An oxidizing agent causes another substance to be oxidized and in the process gets reduced itself. In this reaction, O₂ (oxygen) is allowing C8H7ON to lose electrons and hence, acts as the oxidizing agent.
To identify the oxidizing agent, one must look at the changes in oxidation states of the elements involved in the reaction. As O₂ is reduced and facilitates the oxidation of another substance, it is considered the oxidizing agent. So, the correct answer to the question is option 2) O₂.