Question

What are the factors affecting the dissolving rate of a solid?

Answer 1

There are several

Explanation:

This depends at what level you are studying as to how much explanation is required in the answer.

Possible answers could include whether the solid is ionic or covalent; hence its solubility in whatever solvent is being used.

Presumably the solvent is water.

The temperatures of the water changes the amount of solid that will dissolve into solution and the rate. Sugar dissolves faster in hot coffee. Surface area of the solid affects rate as well. Granulated sugar dissolves in your coffee faster than sugar cubes.
Stirring or shaking increases rate of dissolving.