Which of the following aqueous solutions has osmotic pressure nearest to pure solvent ?

Options

A. `Na_(2)SO_(4)`
B. `BaCl_(2)`
C. `Al_(2)(SO_(4))_(3)`
D. `C_(12)H_(22)O_(11)`

Answer

To determine which of the given aqueous solutions has osmotic pressure nearest to that of pure solvent, we can follow these steps:

### Step 1: Understand the Concept of Osmotic Pressure
Osmotic pressure (π) is given by the formula:
\[ \pi = C R T I \]
Where:
- \(C\) = concentration of the solution
- \(R\) = gas constant
- \(T\) = temperature
- \(I\) = Van't Hoff factor (number of particles the solute dissociates into)

### Step 2: Analyze the Given Solutions
We need to evaluate the Van't Hoff factor (I) for each of the given solutions to determine their osmotic pressures. The solution with the lowest Van't Hoff factor will have osmotic pressure closest to that of pure solvent.

1. **Na2SO4**:
- Dissociates into 2 Na⁺ and 1 SO₄²⁻.
- \(I = 2 + 1 = 3\)

2. **BaCl2**:
- Dissociates into 1 Ba²⁺ and 2 Cl⁻.
- \(I = 1 + 2 = 3\)

3. **Aluminum sulfate (Al2(SO4)3)**:
- Dissociates into 2 Al³⁺ and 3 SO₄²⁻.
- \(I = 2 + 3 = 5\)

4. **C12H22O11 (Sucrose)**:
- This is a non-electrolyte and does not dissociate.
- \(I = 1\)

### Step 3: Compare the Van't Hoff Factors
Now we compare the values of \(I\) for each solution:
- Na2SO4: \(I = 3\)
- BaCl2: \(I = 3\)
- Aluminum sulfate: \(I = 5\)
- C12H22O11: \(I = 1\)

### Step 4: Determine the Solution with Lowest Osmotic Pressure
The solution with the lowest Van't Hoff factor (I) will have the osmotic pressure nearest to that of pure solvent. Here, C12H22O11 has the lowest \(I\) value of 1.

### Conclusion
Thus, the aqueous solution with osmotic pressure nearest to pure solvent is **C12H22O11 (Sucrose)**.

### Final Answer
**C12H22O11 (Sucrose)**

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