Problem: 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)

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 (ΔT­_f) is given by:

$\boxed{{\mathbf{\Delta T}}_{\mathbf{f}}\mathbf{=}{\mathbf{T}}_{\mathbf{f}\mathbf{,}\mathbf{ }\mathbf{pure}\mathbf{ }\mathbf{solvent}}\mathbf{-}{\mathbf{T}}_{\mathbf{f}\mathbf{,}\mathbf{ }\mathbf{solution}}}$

The change in freezing point is also related to the molality of the solution:

$\boxed{{\mathbf{\Delta T}}_{\mathbf{f}}\mathbf{=}{\mathbf{imK}}_{\mathbf{f}}}$

where:

i = van’t Hoff factor

m = molality of the solution (in m or mol/kg)

K_f = freezing point depression constant (in ˚C/m) of the solvent