Question

Calculate osmotic pressure of 0.1 M aqueous solution of an electrolyte at 300 K if van't Hoff factor is 1.125. [R = 0.0821 atmdm$^3$ K$^{-1}$ mol$^{-1}$]

• A. 2.15 atm
• B. 2.41 atm
• C. 2.77 atm
• D. 3.25 atm

Hint:

The value of $RT$ at 300 K (with $R=0.0821$) is approximately 24.63.

Answer 1

The Correct Option is C

Step 1: Formula
$\pi = iCRT$

Step 2: Calculation
Given: $i = 1.125$, $C = 0.1\text{ M}$, $R = 0.0821$, $T = 300\text{ K}$.
$\pi = 1.125 \times 0.1 \times 0.0821 \times 300$
$\pi = 1.125 \times 2.463$
$\pi \approx 2.771$ atm.

Step 3: Conclusion
The osmotic pressure is 2.77 atm.
Final Answer: (C)