Question

The osmotic pressure of 0.01 molar solution of an electrolyte is found to be 0.65 bar at 27°C. The van’t Hoff factor of the electrolyte is (R = 0.083 bar L K$^{-1}$ mol$^{-1}$)

• A. 2.610
• B. 1.610
• C. 2.305
• D. 1.805

Hint:

To find van’t Hoff factor, apply the relation $\pi = iCRT$ where i is the number of ions formed from one formula unit.

Answer 1

The Correct Option is A

Use the formula $\pi = iCRT$
Given: $\pi = 0.65$ bar, $C = 0.01$ mol/L, $R = 0.083$ bar·L·K$^{-1}$·mol$^{-1}$, $T = 300$ K
$0.65 = i \times 0.01 \times 0.083 \times 300$
$i = \frac{0.65}{0.249} \approx 2.610$