Final answer:
In the redox reaction CH₄+2O₂⟶ CO₂+2H₂O, oxygen (O₂) is the oxidizing agent because it gains electrons and is reduced from an oxidation state of 0 to -2 in water (H₂O), while carbon in CH₄ is oxidized.
Step-by-step explanation:
To identify the oxidizing agent in the redox reaction CH₄+2O₂⟶ CO₂+2H₂O, one must look at the changes in oxidation states of the elements involved. In this reaction, carbon in CH₄ is oxidized from an oxidation state of -4 to +4 in CO₂. The oxygen in O₂ is reduced as its oxidation state changes from 0 in dioxygen to -2 in water (H₂O).
Oxygen (O₂) is the oxidizing agent because it accepts electrons during the reaction. We can also view this process as a combustion reaction where methane (CH₄) is the fuel, being oxidized, and thus acting as the reducing agent. Therefore, in the oxidation of methane, the oxygen molecule (O₂) is the entity that is gaining electrons and is reduced, defining its role as the oxidizing agent.