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

• A. Color of the reactants
• B. Volume of the container (for gases)
• C. Concentration of reactants
• D. Presence of a catalyst

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 effectively reactant particles collide.
2. Recognize that the concentration of reactants influences the reaction rate because higher concentration means more particles per unit volume, leading to more frequent collisions.
3. Know that the volume of the container affects the reaction rate for gases because changing the volume changes the pressure and concentration of gas molecules, thus affecting collision frequency.
4. Identify that the presence of a catalyst increases the reaction rate by providing an alternative reaction pathway with a lower activation energy, allowing more collisions to result in a reaction.
5. Note that the color of the reactants generally does not influence the reaction rate directly, as it is not related to collision frequency or energy barriers.