The freezing point of a 1.00 molal aqueous solution of calcium chloride (cacl2) is lower than the freezing point of a 1.00 molal aqueous solution of ethylene glycol (c2h6o2). why are the freezing points of the two solutions different?

The calcium chloride is an electrolyte salt, so the frezzing point of solution must be higher than ethylene glycol.

Explanation:

This is the colligative property for this question: Frezzing point depression

ΔTf = Kf · molal · i

ΔTf = T° fussion solvent pure - T° fussion solution

As both solutions are the same in molality and the solvent is water, the formula stands the same but the Calcium Chloride is a salt which is dissociated in water like this:

CaCl₂ → Ca²⁺  + 2Cl⁻

We have 3 moles of ions, so this value modiffy the formula with the Van't Hoff Factor (number of ion particles per individual molecule of solute).

Ethyleneglycol  is a non-electrolytic organic compound (It is often used 1 as the i).

Let's see the formula in both:

0° - T° fussion solution = Kf · molal · 3 → CaCl2

0° - T° fussion solution = Kf · molal · 1 → C2H6O2