Which of the following factors can decrease the rate of a chemical reaction?

• A. Increasing the surface area of a solid reactant
• B. Adding a catalyst
• C. Increasing the concentration of reactants
• D. Lowering the temperature

Answer: (D)

Verified step by step guidance

1. Understand that the rate of a chemical reaction depends on factors that affect how often and how energetically reactant particles collide.
2. Recall that increasing the surface area of a solid reactant generally increases the reaction rate because more particles are exposed to react.
3. Know that adding a catalyst increases the reaction rate by lowering the activation energy, allowing more collisions to be effective.
4. Recognize that increasing the concentration of reactants increases the reaction rate by increasing the frequency of collisions between reactant particles.
5. Identify that lowering the temperature decreases the reaction rate because it reduces the kinetic energy of particles, leading to fewer effective collisions.