Question

The freezing point of a solution composed of 10.0 g of KCl in 100 g of water is 4.5°C. Calculate the van't Hoff factor, \(i\), for this solution.

• A. 2.50
• B. 1.8
• C. 1.2
• D. 1.3

Hint:

The van't Hoff factor \( i \) is the number of particles into which a solute dissociates in solution.

Answer 1

The Correct Option is A

Step 1: Use the freezing point depression formula.
The formula for freezing point depression is: \[ \Delta T_f = i K_f m \] where \( \Delta T_f \) is the change in freezing point, \( i \) is the van't Hoff factor, \( K_f \) is the cryoscopic constant, and \( m \) is the molality.
Step 2: Calculation.
By rearranging the formula and substituting the known values, we calculate the van't Hoff factor \(i = 2.50\).
Final Answer: \[ \boxed{2.50} \]