Which of the following aqueous solution should have the highest boiling point ?

Options

A. 1.0 M NaOH
B. `1.0 M Na_(2)SO_(4)`
C. `1.0 M NH_(4)NO_(3)`
D. `1.0 M KNO_(3)`

Explanation

To determine which of the given aqueous solutions has the highest boiling point, we will use the concept of boiling point elevation, which is influenced by the van 't Hoff factor (i). The van 't Hoff factor indicates the number of particles into which a solute dissociates in solution. The more particles present, the higher the boiling point elevation.

### Step-by-Step Solution:

1. **Identify the Solutions**: The given solutions are:
- NaOH
- H₂SO₄ (sulfuric acid)
- NH₄NO₃ (ammonium nitrate)
- KNO₃ (potassium nitrate)

2. **Determine the van 't Hoff Factor (i)**:
- **For NaOH**:
- Dissociates into Na⁺ and OH⁻.
- \( i = 2 \) (1 Na⁺ + 1 OH⁻)

- **For H₂SO₄**:
- Dissociates into 2 H⁺ and SO₄²⁻.
- \( i = 3 \) (2 H⁺ + 1 SO₄²⁻)

- **For NH₄NO₃**:
- Dissociates into NH₄⁺ and NO₃⁻.
- \( i = 2 \) (1 NH₄⁺ + 1 NO₃⁻)

- **For KNO₃**:
- Dissociates into K⁺ and NO₃⁻.
- \( i = 2 \) (1 K⁺ + 1 NO₃⁻)

3. **Compare the van 't Hoff Factors**:
- NaOH: \( i = 2 \)
- H₂SO₄: \( i = 3 \)
- NH₄NO₃: \( i = 2 \)
- KNO₃: \( i = 2 \)

4. **Determine the Solution with the Highest Boiling Point**:
- The boiling point elevation is directly proportional to the van 't Hoff factor. The solution with the highest van 't Hoff factor will have the highest boiling point.
- Among the calculated factors, H₂SO₄ has the highest van 't Hoff factor of 3.

5. **Conclusion**:
- Therefore, the aqueous solution that should have the highest boiling point is **H₂SO₄ (sulfuric acid)**.

### Final Answer:
**H₂SO₄ (sulfuric acid) has the highest boiling point among the given solutions.**