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