Question

Calculate the osmotic pressure of 0.2 M aqueous solution of electrolyte at 300 K. If van't Hoff factor is 1.6 [R = 0.0821 atm dm$^3$ K$^{-1}$ mol$^{-1}$].

• A. 7.21 atm
• B. 7.88 atm
• C. 8.81 atm
• D. 8.32 atm

Hint:

Always include the van't Hoff factor ($i$) in colligative property calculations for electrolytes.

Answer 1

The Correct Option is B

Step 1: Formula
$\pi = iCRT$.
Step 2: Substitution
$i = 1.6$, $C = 0.2$ M, $R = 0.0821$, $T = 300$ K.
$\pi = 1.6 \times 0.2 \times 0.0821 \times 300$.
Step 3: Calculation
$\pi = 0.32 \times 24.63 = 7.8816$ atm.
Step 4: Conclusion
The osmotic pressure is 7.88 atm.
Final Answer:(B)