Which of the following would most likely decrease the rate of most chemical reactions?

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

Answer: (B)

Verified step by step guidance

1. Understand that the rate of a chemical reaction depends on factors such as temperature, concentration, surface area, and catalysts.
2. Recall that increasing surface area of a solid reactant generally increases the reaction rate because more particles are exposed to react.
3. Recognize that increasing the concentration of reactants usually increases the reaction rate by increasing the frequency of collisions between reactant molecules.
4. Know that adding a catalyst provides an alternative reaction pathway with a lower activation energy, thus increasing the reaction rate.
5. Identify that lowering the temperature decreases the kinetic energy of molecules, reducing the frequency and energy of collisions, which most likely decreases the rate of the reaction.