A 0.100 m K₂SO₄ solution has a freezing point of −0.43°C. What is the van't Hoff factor for this solution? K_f = 1.86°C/m A)0.77 B)1.0 C)2.3 D)3.0 E)3.0

Question

A 0.100 m K₂SO₄ solution has a freezing point of −0.43°C. What is the van't Hoff factor for this solution? K_f = 1.86°C/m A)0.77 B)1.0 C)2.3 D)3.0 E)>3.0

Quizplus · Accepted Answer

The van't Hoff factor (i) can be calculated using the formula:
ΔTf = iKf*m
where ΔTf is the freezing-point depression, Kf is the freezing-point depression constant for the solvent, and m is the molality of the solution.
By rearranging the formula we get:
i = ΔTf / (Kf * m)

Substituting the given values:
ΔTf = (freezing point of pure solvent - freezing point of solution) = (0°C - (-0.43°C)) = 0.43°C
Kf for water = 1.86°C/m
m = 0.100 mol/kg

i = 0.43°C / (1.86°C/m * 0.100 mol/kg) = 2.31
So the van't Hoff factor is 2.3, which is closest to option C.

A 0100 M K2SO4 Solution Has a Freezing Point of −0

A 0100 M K₂SO₄ Solution Has a Freezing Point of −0