Consider the following solutions: \(0.010 m \mathrm{Na}_{3} \mathrm{PO}_{4}\) in water \(0.020 \mathrm{m} \mathrm{CaBr}_{2}\) in water \(0.020 \mathrm{m} \mathrm{KCl}\) in water \(0.020 \mathrm{m}\) HF in water (HF is a weak acid.) a. Assuming complete dissociation of the soluble salts, which solution(s) would have the same boiling point as \(0.040 \mathrm{m}\) \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\) in water? \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\) is a nonelectrolyte. b. Which solution would have the highest vapor pressure at \(28^{\circ} \mathrm{C} ?\) c. Which solution would have the largest freezing-point depression?

Since the given molality values are provided directly, we don't need to make any calculations for molality. We already have the molality for each of the solutions: - 0.010 m Na3PO4 - 0.020 m CaBr2 - 0.020 m KCl - 0.020 m HF - 0.040 m C6H12O6 (reference)

For non-electrolytes like C6H12O6, i=1. For electrolytes, i is equal to the number of ions produced on dissociation: - Na3PO4: 3 Na+ + PO4^3- → i = 4 - CaBr2: Ca^2+ + 2 Br- → i = 3 - KCl: K+ + Cl- → i = 2 - HF: weak acid, doesn't completely dissociate → i ≈ 1

Multiply molality and the number of ions produced(i) for each solution: - Na3PO4: 0.010 m × 4 = 0.040 - CaBr2: 0.020 m × 3 = 0.060 - KCl: 0.020 m × 2 = 0.040 - HF: 0.020 m × 1 ≈ 0.020 - C6H12O6: 0.040 m × 1 = 0.040 (reference) a) The solutions which have the same i×molality as the C6H12O6 solution will have the same boiling point. Both Na3PO4 and KCl solutions show the same i×molality value (0.040) as C6H12O6. b) The highest vapor pressure will be produced by the solution with the lowest molality. In this case, the HF solution has the lowest i×molality, so it will have the highest vapor pressure at 28°C. c) The largest freezing-point depression will occur in the solution with the highest i×molality. So, CaBr2 with i×molality value of 0.060 will have the largest freezing-point depression. Answers: a) The Na3PO4 and KCl solutions will have the same boiling point as the 0.040 m C6H12O6 solution. b) The HF solution will have the highest vapor pressure at 28°C. c) The CaBr2 solution will have the largest freezing-point depression.