An increase in which of the following results in a decrease in the rate of a chemical reaction?

• A. Concentration of reactants
• B. Temperature
• C. Activation energy
• D. Surface area of solid reactants

Answer: (C)

Verified step by step guidance

1. Understand that the rate of a chemical reaction depends on several factors, including concentration of reactants, temperature, activation energy, and surface area of solid reactants.
2. Recall that increasing the concentration of reactants generally increases the reaction rate because more reactant particles are available to collide and react.
3. Recognize that increasing temperature usually increases the reaction rate because particles have more kinetic energy, leading to more frequent and energetic collisions.
4. Know that increasing the surface area of solid reactants increases the reaction rate by exposing more particles to react, facilitating more collisions.
5. Identify that activation energy is the minimum energy required for a reaction to occur; an increase in activation energy means fewer particles have enough energy to react, thus decreasing the reaction rate.