The osmotic pressure of a solution containing 0.3 mol of solute per litre at 300 K is

Explanation

To calculate the osmotic pressure (\( \pi \)) of a solution containing 0.3 mol of solute per liter at 300 K, we can use the formula:

\[ \pi = CRT \]

Where:
- \( \pi \) = osmotic pressure
- \( C \) = concentration of the solution (in mol/L)
- \( R \) = ideal gas constant (0.0821 L·atm/(K·mol))
- \( T \) = temperature in Kelvin

### Step-by-Step Solution:

1. **Identify the given values:**
- Concentration (\( C \)) = 0.3 mol/L
- Temperature (\( T \)) = 300 K
- Gas constant (\( R \)) = 0.0821 L·atm/(K·mol)

2. **Substitute the values into the osmotic pressure formula:**
\[ \pi = C \cdot R \cdot T \]
\[ \pi = 0.3 \, \text{mol/L} \cdot 0.0821 \, \text{L·atm/(K·mol)} \cdot 300 \, \text{K} \]

3. **Calculate the product:**
- First, calculate \( 0.3 \cdot 0.0821 \):
\[ 0.3 \cdot 0.0821 = 0.02463 \]
- Then, multiply by 300:
\[ 0.02463 \cdot 300 = 7.389 \]

4. **Final result:**
\[ \pi \approx 7.389 \, \text{atm} \]

### Conclusion:
The osmotic pressure of the solution is approximately 7.389 atm.