Chapter 13

Q. 13.4.2

The ionic compound CaCl_{2} is soluble in water. Calculate the osmotic pressure generated when 0.249 g of CaCl_{2} is dissolved in 151 mL of an aqueous solution at 298 K. The van’t Hoff factor for CaCl_{2} in this solution is 2.8.


Verified Solution

You are asked to calculate osmotic pressure for a solution containing an ionic solute.
You are given the mass of solute in the solution, the volume of the solution, the temperature of the solution, and the van’t Hoff factor for the ionic solute.

0.249 g CaCl_{2}\times \frac{1\text{ mol CaCl}_{2}}{111.0 \text{ g}} = 0.002244 mol CaCl_{2}

\frac{0.002244 \text{ mol CaCl}_{2}}{0.151 \text{ L}} = 0.0146 M

Π = cRTi = (0.0149 M)(0.082057 L · atm/K · mol)(298 K)(2.8) = 1.0 atm