A 0.100 m solution of ZnCl₂ in water has a freezing point depression of 0.495 ° C. If the freezing point depression constant (k_f) for water is 1.86 ° C/m, what is the van't Hoff i factor for this solution?

Question

Quizplus · Accepted Answer

The formula to calculate the van't Hoff i factor is:

i = (ΔTf of pure solvent) / (ΔTf of solution)

ΔTf of pure solvent is 1.86 °C (given in the problem statement).

ΔTf of solution can be calculated using the formula:

ΔTf = Kf * m * i

where Kf is the freezing point depression constant for water (1.86 °C/m), m is the molality of the solution (which is equal to the number of moles of solute per kg of solvent), and i is the van't Hoff i factor.

We are given the molality of the solution (0.100 m), and ΔTf of solution (0.495 °C). Plugging these values into the formula above, we get:

0.495 = 1.86 * 0.100 * i

Solving for i, we get:

i = 0.495 / (1.86 * 0.100) = 2.66

Therefore, the van't Hoff i factor for this solution is 2.66, which is closest to choice D (2.66).

A 0100 M Solution of ZnCl2 in Water Has a Freezing

A 0100 M Solution of ZnCl₂ in Water Has a Freezing