Final answer:
The 0.5M Na3PO4 solution would have the highest boiling point because it dissociates into the greatest number of particles, four (3 Na+ and 1 PO43-), resulting in the highest boiling point elevation among the options given.
Step-by-step explanation:
In order to determine which aqueous solution would have the highest boiling point, we need to understand the concept of boiling point elevation, which is a colligative property. This property demonstrates that the boiling point of a solution is higher than that of the pure solvent due to the presence of solute particles. The factor that affects the boiling point elevation in an ideal situation is the amount of solute particles in the solution, which can be predicted using the van 't Hoff factor.
When comparing the boiling points of various 0.5M solutions of sodium salts, we look at the van 't Hoff factor, or the number of particles that the compound dissociates into when dissolved. For Na2SO4 (option a), it dissociates into three particles: 2 Na+ and 1 SO42-. Option b, Na3PO4, dissociates into four ions: 3 Na+ and 1 PO43-. NaCl (option c) dissociates into two particles: Na+ and Cl-. Finally, Na2CO3 (option d), like Na2SO4, dissociates into three particles: 2 Na+ and 1 CO32-.
Therefore, the 0.5M Na3PO4 solution would have the highest boiling point among the given choices because it produces the greatest number of dissolved particles, leading to the highest boiling point elevation.