Which of the following will NOT increase the rate of a reaction between a solid and a solution?
- A. Raising the temperature
- B. Powdering the solid
- C. Increasing the volume of solvent without adding more solute
- D. Adding a suitable catalyst
Explanation
Adding solvent alone dilutes the solution, so the concentration of the reacting species falls and collisions become less frequent, which slows the reaction rather than speeding it. Heating, increasing surface area and adding a catalyst all raise the frequency or the effectiveness of collisions. Note that a larger volume gives more total reactant but a lower concentration, and rate depends on concentration.