Question

assume ideal van't Hoff factors where applicable. Choose the aqueous solution below with the lowest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.
A. 0.075 m Li I
B. 0.075 m (NH4)3PO4
C. 0.075 m NaIO4
D. 0.075 m KCN
E. 0.075 m KNO2

Answer 1

Answer:

B. 0.075 m (NH4)3PO4

Explanation:

Our strategy here is to recall the van´t Hoff factor, i, for the colligative properties of electrolyte solutions which appears as the consequence that electrolytes disociate completely in their solutions in water.

Thus in this problem we need to determine i and then realize the one with the lowest freezing point will have the biggest  i ( all the concentrations are equal) since

ΔTf = i m Kf

Substance  van´t Hoff factor

Li I                             2

(NH4)3PO4              4

NaIO4                       2

KCN                          2

KNO2                       2

The correct answer is B. 0.075 m (NH4)3PO4