Which type of substance is commonly used to increase the decomposition rate of hydrogen peroxide (H_2O_2)?

• A. Inhibitor
• B. Reactant
• C. Solvent
• D. Catalyst

Answer: (D)

Verified step by step guidance

1. Understand the role of each substance type in a chemical reaction: a reactant is consumed during the reaction, a solvent dissolves substances but does not change the reaction rate, an inhibitor slows down the reaction, and a catalyst increases the reaction rate without being consumed.
2. Recall that hydrogen peroxide (H_2O_2) naturally decomposes into water and oxygen, but this process can be slow under normal conditions.
3. Identify that a catalyst is a substance that speeds up the decomposition of hydrogen peroxide by providing an alternative reaction pathway with a lower activation energy.
4. Recognize common catalysts for H_2O_2 decomposition, such as manganese dioxide (MnO_2) or catalase enzyme, which increase the rate without being consumed.
5. Conclude that the substance type used to increase the decomposition rate of hydrogen peroxide is a catalyst.