Which of the following solutions will have highest boiling point:

Options

A. 1% glucose in water
B. 1% sucrose in water
C. `1%NaCI` in water
D. 1% urea in water

Answer

To determine which solution has the highest boiling point, we will analyze the colligative properties of the given solutions. The boiling point elevation (ΔTb) is a colligative property that depends on the number of solute particles (ions or molecules) in a solution.

### Step-by-Step Solution:

1. **Understand Colligative Properties**:
- Colligative properties depend on the number of solute particles in a solution, not on their identity. The boiling point elevation can be expressed as:
\[ \Delta T_b = i \cdot K_b \cdot m \]
where \(i\) is the van 't Hoff factor (number of particles the solute dissociates into), \(K_b\) is the ebullioscopic constant, and \(m\) is the molality of the solution.

2. **Identify the Solutions**:
- The solutions mentioned in the question include NaCl, glucose, sucrose, and urea.

3. **Determine the van 't Hoff Factor (i)**:
- **NaCl**: Dissociates into 2 ions (Na⁺ and Cl⁻), so \(i = 2\).
- **Glucose**: Does not dissociate (non-electrolyte), so \(i = 1\).
- **Sucrose**: Also does not dissociate (non-electrolyte), so \(i = 1\).
- **Urea**: Does not dissociate (non-electrolyte), so \(i = 1\).

4. **Compare the Number of Particles**:
- Since NaCl dissociates into 2 ions, it contributes more solute particles compared to glucose, sucrose, and urea, which do not dissociate.

5. **Conclusion**:
- Among the given solutions, 1% NaCl in water will have the highest boiling point due to the higher number of particles (ions) present in the solution.

### Final Answer:
The solution with the highest boiling point is **1% NaCl in water**.