To determine which solute raises the boiling point of water the most, we can use the principle of colligative properties, which states that the boiling point elevation of a solvent is related to the number of solute particles in solution. The formula for boiling point elevation is:
\[ \Delta T_b = i \cdot K_b \cdot m \]
Where:
- \(\Delta T_b\) is the boiling point elevation,
- \(i\) is the van 't Hoff factor (the number of particles the compound dissociates into),
- \(K_b\) is the ebullioscopic constant of the solvent (water in this case),
- \(m\) is the molality of the solution.
Now, let's look at each option:
A. Lithium Chloride (LiCl): Dissociates into 2 particles (Li⁺ and Cl⁻), so \(i = 2\).
B. Sodium Chloride (NaCl): Dissociates into 2 particles (Na⁺ and Cl⁻), so \(i = 2\).
C. Sucrose (C12H22O11): Does not dissociate, so \(i = 1\).
D. Sodium Phosphate (Na3PO4): Dissociates into 4 particles (3 Na⁺ and 1 PO4³⁻), so \(i = 4\).
E. Magnesium Bromide (MgBr2): Dissociates into 3 particles (1 Mg²⁺ and 2 Br⁻), so \(i = 3\).
Now, comparing the values of \(i\):
- LiCl: \(i = 2\)
- NaCl: \(i = 2\)
- Sucrose: \(i = 1\)
- Na3PO4: \(i = 4\)
- MgBr2: \(i = 3\)
Since sodium phosphate (Na3PO4) has the highest van 't Hoff factor (\(i = 4\)), it will raise the boiling point of water the most.
The answer is D. ionic sodium phosphate (Na3PO4).
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