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 compound has the highest Van't Hoff factor (i), we need to analyze the dissociation of each compound in water. The Van't Hoff factor is defined as the number of particles in solution after dissociation divided by the number of particles before dissociation.

### Step-by-Step Solution:

1. **Identify the Compounds**: We have four compounds to consider:
- NaCl (Sodium Chloride)
- MgCl2 (Magnesium Chloride)
- Na3PO4 (Sodium Phosphate)
- Urea (NH2CO-NH2)

2. **Analyze NaCl**:
- NaCl dissociates in water into Na⁺ and Cl⁻.
- Before dissociation: 1 particle (NaCl)
- After dissociation: 2 particles (Na⁺ and Cl⁻)
- Van't Hoff factor (i) = 2/1 = 2

3. **Analyze MgCl2**:
- MgCl2 dissociates in water into Mg²⁺ and 2 Cl⁻.
- Before dissociation: 1 particle (MgCl2)
- After dissociation: 3 particles (Mg²⁺ and 2 Cl⁻)
- Van't Hoff factor (i) = 3/1 = 3

4. **Analyze Na3PO4**:
- Na3PO4 dissociates in water into 3 Na⁺ and 1 PO4³⁻.
- Before dissociation: 1 particle (Na3PO4)
- After dissociation: 4 particles (3 Na⁺ and 1 PO4³⁻)
- Van't Hoff factor (i) = 4/1 = 4

5. **Analyze Urea**:
- Urea does not dissociate in water; it remains as one particle.
- Before dissociation: 1 particle (Urea)
- After dissociation: 1 particle (Urea)
- Van't Hoff factor (i) = 1/1 = 1

6. **Compare the Van't Hoff Factors**:
- NaCl: i = 2
- MgCl2: i = 3
- Na3PO4: i = 4
- Urea: i = 1

7. **Conclusion**:
- The highest Van't Hoff factor is for Sodium Phosphate (Na3PO4), which has a value of 4.

### Final Answer:
The Van't Hoff factor will be highest for Sodium Phosphate (Na3PO4).

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