Question

Arrange the following solutions as directed:

0.01 M KCl, 0.01 M sucrose, 0.01 M Na₂SO₄ (in the order of increasing freezing points)

Explain the reason for your answers also.

Answer 1

0.01 M Na₂SO₄ < 0.01 M KCl < 0.01 M sucrose

Reason:

All solutions have the same concentration, but the solutes dissociate to different extents. Greater dissociation means more particles in solution, which causes greater freezing point depression. Hence, Na₂SO₄ has the lowest freezing point and sucrose the highest.