Final answer:
The van't Hoff factor for CaCl₂ can be determined by measuring the freezing point depression or boiling point elevation of its aqueous solution and using the formula ΔTf = i⋅kf⋅m or ΔTb = i⋅Kb⋅m. This factor indicates the degree of dissociation in solution and varies from the ideal value due to ionic interactions.
Step-by-step explanation:
To experimentally determine the van't Hoff factor for CaCl₂, you can measure the depression of freezing point or elevation of boiling point of its aqueous solution. For CaCl₂, the ideal van't Hoff factor (i) is 3, because in solution it is expected to dissociate into three ions: one Ca²⁺ and two Cl⁻ ions.
First, prepare a dilute solution of known molality of CaCl₂. Then, measure the freezing point depression (ΔTf) or the boiling point elevation (ΔTb). Using these measurements, you can calculate the experimental van't Hoff factor 'i' using the formula ΔTf = i⋅kf⋅m or ΔTb = i⋅Kb⋅m, where kf and Kb are the freezing point depression and boiling point elevation constants of the solvent, and m is the molality of the solution.
The experimental van't Hoff factor can differ from the ideal factor due to ion pairing and other interactions in the solution, particularly at higher concentrations. By comparing the experimental 'i' value to the ideal value, you can assess how completely the solute dissociates in a given solvent and at a given concentration.