Final answer:
Dissolved particles affect boiling point elevation. The solution with glucose (C₆H₁₂O₆) has the lowest boiling point because it does not dissociate into ions, producing fewer particles compared to ionic compounds.The correct option is 3.
Step-by-step explanation:
To determine which solution has the lowest boiling point, we need to consider the impact of dissolved particles on the boiling point elevation, known in chemistry as colligative properties. The boiling point elevation of a solution depends on the number of particles present in solution, which is dictated by both the concentration of the solute and the extent to which it dissociates into ions.
Each of the given compounds affects the boiling point differently:
- Na₃PO₄ (sodium phosphate) dissociates into four ions (three Na+ ions and one PO4^3- ion).
- Ca(NO₃)² (calcium nitrate) dissociates into three ions (one Ca²+ ion and two NO3- ions).
- Glucose (C₆H₁₂O₆) does not dissociate; it remains a single molecule in solution.
- KCl (potassium chloride) dissociates into two ions (one K+ ion and one Cl- ion).
Considering the van 't Hoff factor (i), which is the number of particles produced per formula unit of solute, we can predict that the boiling point elevation will be greatest for Na₃PO₄, then Ca(NO₃)², followed by KCl, and the least for glucose. Therefore, the solution with glucose will have the lowest boiling point since it produces the least amount of particles upon dissolving.
In conclusion, a solution formed by dissolving 0.75 mol of glucose (C₆H₁₂O₆) in 1.00 kg of water will have the lowest boiling point among the given options.