Final answer:
Hydrogen peroxide (H₂O₂) is the oxidizing agent in the reaction H₂S + H₂O₂ → S + 2 H₂O, as it accepts electrons and gets reduced to water (H₂O), while oxidizing hydrogen sulfide (H₂S) to sulfur (S).
Step-by-step explanation:
To determine which substance is the oxidizing agent in the given reaction H₂S + H₂O₂ → S + 2 H₂O, we need to look at the changes in oxidation states of the reactants. In this reaction, hydrogen sulfide (H₂S) is being oxidized to sulfur (S), while hydrogen peroxide (H₂O₂) is being reduced to water (H₂O).
According to the information given, hydrogen sulfide is a good reducing agent, meaning it tends to lose electrons and thereby increases in oxidation state during a chemical reaction. On the other hand, hydrogen peroxide is known to be a powerful oxidizing agent, as it readily accepts electrons.
In the context of this reaction, H₂O₂ is the substance that is gaining electrons (being reduced) and hence is the oxidizing agent responsible for the oxidation of H₂S to sulfur (S). Therefore, option 2, H₂O₂, is the oxidizing agent in this reaction.