The Van’t Hoff factor will be highest for:

Options

A. Sodium chloride
B. Magnesium chloride
C. Sodium phosphate
D. Urea

Answer

To determine which substance has the highest Van't Hoff factor (i), we need to analyze the dissociation of each given compound in solution. The Van't Hoff factor is defined as the number of particles (ions or molecules) that a solute produces when it dissolves in a solvent.

### Step-by-Step Solution:

1. **Understanding the Van't Hoff Factor**:
- The Van't Hoff factor (i) is the number of particles formed from one formula unit of a solute when it dissolves in a solution.

2. **Analyzing Sodium Chloride (NaCl)**:
- Sodium chloride dissociates into two ions: Na⁺ and Cl⁻.
- Therefore, the Van't Hoff factor for NaCl is:
\[ i = 2 \]

3. **Analyzing Magnesium Chloride (MgCl₂)**:
- Magnesium chloride dissociates into three ions: Mg²⁺ and 2 Cl⁻.
- Therefore, the Van't Hoff factor for MgCl₂ is:
\[ i = 3 \]

4. **Analyzing Sodium Phosphate (Na₃PO₄)**:
- Sodium phosphate dissociates into four ions: 3 Na⁺ and PO₄³⁻.
- Therefore, the Van't Hoff factor for Na₃PO₄ is:
\[ i = 4 \]

5. **Analyzing Urea (NH₂CONH₂)**:
- Urea is a non-electrolyte and does not dissociate in solution.
- Therefore, the Van't Hoff factor for urea is:
\[ i = 1 \]

6. **Comparing the Van't Hoff Factors**:
- From the calculations:
- NaCl: i = 2
- MgCl₂: i = 3
- Na₃PO₄: i = 4
- Urea: i = 1
- The highest Van't Hoff factor is for sodium phosphate (Na₃PO₄) with a factor of 4.

### Conclusion:
The Van't Hoff factor will be highest for sodium phosphate (Na₃PO₄), which has a Van't Hoff factor of 4.