Question

Find the osmotic pressure of 0.01 M solution at 25 °C \((R = 0.0821 \text{L atm mol}^{-1}\text{K}^{-1})\)

• A. \(0.201\) atm
• B. \(0.245\) atm
• C. \(0.082\) atm
• D. \(0.41\) atm

Hint:

Apply pi = CRT with T converted to kelvin.

Answer 1

The Correct Option is B

Step 1: Approach
Treat the solute as a gas that fills the solution volume.

Step 2: Setup
Number of moles per litre is $C=0.01$. Temperature is $298$ K.
\[ \pi = C R T = (0.01)(0.0821)(298) \]

Step 3: Arithmetic
$0.0821\times298=24.46$, and multiplying by $0.01$ gives $0.2446$ atm, which rounds to $0.245$ atm.

Step 4: Conclusion
This agrees with option (B). Dropping the temperature factor would give 0.0008 atm per mole-litre unit, which matches none of the other choices.

Final Answer:
The osmotic pressure is about 0.245 atm, option (B). \[ \boxed{0.245\ \text{atm}} \]