Answer:
- <u><em>0.2 mol of CaCl</em></u><em><u>₂</u></em>
Explanation:
<em>Freezing point</em> depression of a solution, when a nonvolatile solute is dissolved in a solvent, is a colligative property, which means that it depends on the number of particles of solute dissolved.
The equation is:
Where:
- ΔTf is the decrease in the freezing point
- m is the molal concentration
- kf is the molal freezing point depression constant, which depends on the solvent
- i is the nan't Hoff factor, which accounts for the dissociation of ionic compounds.
Since the volume is the same for all the solutoins, the molal concentration will be higher for those solutions with more number of moles. Then, cross out the first two choices.
Since CaCl₂, in ideal conditions, dissociates into 1 Ca²⁺ ion and 2 Cl⁻ ions, the van't Hoff factor is 3, while for the molcecular C₆H₁₂O₆ it is 1.
Thus, the lowest freezing point will be produced by the sample of 0.2 mol of CaCl₂.