We’re being asked to list the given aqueous solutions in order of decreasing freezing point.
Recall that the freezing point of a solution is lower than that of the pure solvent and the change in freezing point (ΔTf) is given by:
The change in freezing point is also related to the molality of the solution:
i = van’t Hoff factor
m = molality of the solution (in m or mol/kg)
Kf = freezing point depression constant (in ˚C/m) of the solvent
Which of the following solutions will have the lowest freezing point? Input the appropriate letter.
A. 35.0 g of C3H8O in 250.0 g of ethanol (C2H5OH)
B. 35.0 g of C4H10O in 250.0 g of ethanol (C2H5OH)
C. 35.0 g of C2H6O2 in 250.0 g of ethanol (C2H5OH)