Question

Which of the following changes would decrease the rate at which a solid solute dissolves in a liquid solvent

O Decreasing pressure
O Decreasing surface area
Increasing rate of stirring
O Increasing temperature

Answer 1

Answer: Decreasing surface area

Step-by-step explanation:

If it was a gas, then decreasing the pressure would lower the dissolving rate. Since it is a solid, decreasing surface area lowers the dissolving rate. This can be explained by the fact that when a solid solute has more surface area, there are more exposed molecules that can collide with the molecules of the solvent and therefore dissolve the solute. For example, 1 teaspoon of sugar granules will dissolve faster that 1 sugar cube (same mass as the teaspoon) because the granules have a higher surface area. Thus, the opposite is true when the surface area decreases.