According to Raoult's Law, which compound will have a higher boiling and lower freezing point?

Raoult's Law states that the vapor pressure of a solvent in a solution is directly proportional to the mole fraction of the solvent in the solution. When a solute is added to a solvent, it affects the boiling point and freezing point of the solvent. The more solute particles that are present in a solution, the more significant the elevation in boiling point and the depression in freezing point.

The key to understanding why potassium sulfate (K2SO4) affects boiling and freezing points the most lies in its dissociation in solution. K2SO4 dissociates into three ions (2 potassium ions and 1 sulfate ion). Compared to other compounds like KCl, MgCl2, and NaCl, which dissociate into fewer particles, K2SO4 contributes more ions to the solution, leading to a larger colligative effect.

The greater the number of particles in solution, the higher the boiling point elevation and the lower the freezing point depression. Therefore, potassium sulfate will create a solution that exhibits a higher boiling point and a lower freezing point than the other compounds mentioned, making it the correct choice in this context.