According to collision theory, which of the following factors increases the rate of a chemical reaction?

• A. Reducing the surface area of solid reactants
• B. Lowering the activation energy by removing a catalyst
• C. Decreasing the temperature
• D. Increasing the concentration of reactants

Answer: (D)

Verified step by step guidance

1. Recall that according to collision theory, the rate of a chemical reaction depends on the frequency and energy of collisions between reactant molecules.
2. Understand that increasing the concentration of reactants increases the number of particles in a given volume, which leads to more frequent collisions.
3. Recognize that reducing the surface area of solid reactants actually decreases the available area for collisions, thus lowering the reaction rate.
4. Know that removing a catalyst raises the activation energy, making it harder for collisions to result in a reaction, so lowering the activation energy by removing a catalyst is incorrect.
5. Remember that decreasing the temperature reduces the kinetic energy of molecules, leading to fewer effective collisions and a slower reaction rate.