Question

A 0.230 m solution of an unknown electrolyte depresses the freezing point of water by 0.821°C. What is the Van't Hoff factor for this electrolyte? The freezing point depression constant for water is 1.86 °C/m. a. 0.521 b. 1.92 c. 2.00 d. 2.30 e. 4.41

Answer 1

i = ΔTf / (Kf * molality)

i = 0.821°C / (1.86 °C/m * 0.230 m)

i = 2.00

The Van't Hoff factor for this electrolyte is 2.00, and the correct answer is (c).