Which of the following changes will generally increase the rate of a chemical reaction?

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

Answer: (C)

Verified step by step guidance

1. Understand that the rate of a chemical reaction depends on factors such as concentration, temperature, surface area, and the presence of catalysts.
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 adding an inert gas at constant volume does not change the concentration of reactants, so it usually does not affect the reaction rate.
4. Know that decreasing the temperature typically decreases the reaction rate because particles have less kinetic energy, leading to fewer effective collisions.
5. Understand that decreasing the surface area of a solid reactant reduces the available area for collisions, thus generally decreasing the reaction rate.