To determine which substance will increase the rate of production of sulfur trioxide (SO₃) in the reaction: \[ 2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g) \] we need to analyze the role of each option in the context of this chemical reaction. ### Correct Option: C. Vanadium (V) oxide **Step-by-Step Explanation:** 1. **Understanding the Reaction:** - The reaction involves sulfur dioxide (SO₂) and oxygen (O₂) reacting to form sulfur trioxide (SO₃). This is an important reaction in the industrial production of sulfuric acid (H₂SO₄) through the Contact Process. 2. **Role of Catalysts:** - A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. Catalysts work by providing an alternative pathway for the reaction with a lower activation energy. 3. **Vanadium (V) Oxide as a Catalyst:** - Vanadium (V) oxide (V₂O₅) is commonly used as a catalyst in the production of sulfur trioxide from sulfur dioxide and oxygen. It facilitates the reaction by lowering the activation energy required for the reaction to proceed, thus increasing the rate at which SO₃ is produced. 4. **Why Other Options Are Incorrect:** - **A. Manganese (IV) oxide (MnO₂):** - While manganese (IV) oxide can act as a catalyst in some reactions, it is not typically used in the production of SO₃. Its catalytic properties are not as effective for this specific reaction compared to vanadium (V) oxide. - **B. Finely divided iron:** - Finely divided iron is not a suitable catalyst for this reaction. Iron is more commonly associated with reactions involving hydrogen or carbon compounds, but it does not effectively catalyze the oxidation of SO₂ to SO₃. - **D. Nickel:** - Nickel is primarily used as a catalyst in hydrogenation reactions and does not play a significant role in the oxidation of sulfur dioxide to sulfur trioxide. Its catalytic properties are not applicable to this specific reaction. ### Summary of Key Points: - The reaction of SO₂ and O₂ to form SO₃ is catalyzed by vanadium (V) oxide (V₂O₅). - Catalysts increase reaction rates by lowering activation energy. - Other options (manganese (IV) oxide, finely divided iron, and nickel) are not effective catalysts for this specific reaction. ### Revision Summary: - **Catalysts** increase reaction rates without being consumed. - **Vanadium (V) oxide (V₂O₅)** is the effective catalyst for the production of SO₃. - Other options do not effectively catalyze the reaction of SO₂ and O₂. - Understanding the role of catalysts is crucial in industrial chemistry processes.