Which of the following conditions will increase the rate of a chemical reaction?

• A. Lowering the surface area of a solid reactant
• B. Adding an inert gas at constant volume
• C. Increasing the concentration of reactants
• D. Decreasing the temperature

Answer: (C)

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. Recognize that increasing the concentration of reactants increases the number of particles per unit volume, leading to more frequent collisions and thus a higher reaction rate.
3. Know that lowering the surface area of a solid reactant actually decreases the reaction rate because fewer particles are exposed for collisions.
4. Realize that adding an inert gas at constant volume does not change the concentration of reactants, so it does not affect the reaction rate.
5. Understand that decreasing the temperature reduces the kinetic energy of particles, leading to fewer effective collisions and a slower reaction rate.