Respuesta :
Answer:
- A) 2.0 BaCl₂ > B) 2.0 NaNO₃ > D) 1.0 K₂SO₃ > C) 1.0 C₆H₁₂O₆
Explanation:
The boiling point of a pure solven increases when a solute is added and a solution is formed.
The increase of the boiling point of a solvent, when a non-volatile solute is added, is a colligative property, meaning that it depends of the number particles of solute dissolved.
The equation that rules the increase of the boiling point is:
- ΔTb = Kb × m × i
Where:
- ΔTb is the increase in the boiling point of the solvent,
- Kb is the boiling molal constant of the solvent, and
- i is the Vant' Hoff factor, which accounts for the number of ions when the solute is a ionic compound.
Then, since Kb is constant (because it is the same solvent for all the solutions), you must look at the product m × i.
For ionic solutes you assume 100% ionization, which drives to:
Solution Ionization i m m × i
A) 2.0 BaCl₂ Ba⁺² + 2Cl⁻ 3 2.0 6.0 ↔ highest
B) 2.0 NaNO₃ Na⁺ + NO₃⁻ 2 2.0 4.0 ↔ second
C) 1.0 C₆H₁₂O₆ none 1 1.0 1.0 ↔ lowest (fourth)
D) 1.0 K₂SO₃ 2K⁺ + SO₃²⁻ 3 1.0 3.0 ↔ third
Then, 6.0 > 4.0 > 3.0 > 1.0 and the final list of the solutions arranged in order from highest boiling point to lowest boiling point is:
- 2.0 BaCl₂ > 2.0 NaNO₃ > 1.0 K₂SO₃ > 1.0 C₆H₁₂O₆
