Which of the following would most effectively increase the rate of decomposition of hydrogen peroxide (H2O2)?

• A. Diluting the hydrogen peroxide solution with water
• B. Adding manganese dioxide (MnO2) as a catalyst
• C. Removing light from the reaction environment
• D. Lowering the temperature of the reaction mixture

Answer: (B)

Verified step by step guidance

1. Understand that the rate of decomposition of hydrogen peroxide (H\_2O\_2) can be influenced by factors such as concentration, temperature, presence of catalysts, and environmental conditions like light exposure.
2. Recall that catalysts increase the rate of a chemical reaction by providing an alternative reaction pathway with a lower activation energy, without being consumed in the process.
3. Analyze each option: Diluting the solution decreases concentration, which generally slows down the reaction rate according to the rate law; removing light may reduce photochemical effects but is not the primary factor here; lowering temperature decreases kinetic energy, thus slowing the reaction.
4. Recognize that adding manganese dioxide (MnO\_2) acts as a catalyst for the decomposition of hydrogen peroxide, significantly increasing the reaction rate by lowering the activation energy.
5. Conclude that among the given options, adding MnO\_2 as a catalyst most effectively increases the rate of hydrogen peroxide decomposition.