Answer:
When the size of a fixed mass of a solid reactant decreases, the rate of reaction increases.
This can be explained using the collision theory, as below:
When the size of a fixed mass of a solid reactant becomes smaller, the total surface area exposed to collision with the particles of the other reactants increases As a result, the frequency of collision among the reacting particles at the surface of the solid reactant increases. This causes the frequency of effective collision to increase. Hence, the rate of reaction increases.
Step-by-step explanation: