Understanding the Concepts
* Vapor Pressure: The pressure exerted by the vapor of a liquid in equilibrium with its liquid phase.
* Raoult's Law: States that the partial vapor pressure of a solvent in a solution is equal to the vapor pressure of the pure solvent multiplied by its mole fraction in the solution.
* Mole Fraction: The ratio of moles of a component to the total moles in a solution.
Steps
1. Identify the Solvent and Solute:
* Solvent: Water (H₂O)
* Solute: Mercury(II) chloride (HgCl₂)
2. Determine the Vapor Pressure of Pure Water:
* At 25°C, the vapor pressure of pure water is approximately 23.76 torr (you can find this value in a table or online).
3. Calculate the Mole Fraction of Water:
* Since the mole fraction of HgCl₂ is 0.163, the mole fraction of water (H₂O) is:
* Mole fraction of H₂O = 1 - mole fraction of HgCl₂ = 1 - 0.163 = 0.837
4. Apply Raoult's Law:
* Vapor pressure of the solution = (Mole fraction of H₂O) * (Vapor pressure of pure H₂O)
* Vapor pressure of the solution = (0.837) * (23.76 torr)
* Vapor pressure of the solution ≈ 19.88 torr
Therefore, the vapor pressure of the water solution containing 0.163 mole fraction HgCl₂ at 25°C is approximately 19.88 torr.
Important Note:
* This calculation assumes that HgCl₂ is a non-volatile solute, meaning it doesn't contribute significantly to the vapor pressure of the solution.
* The actual vapor pressure of the solution might be slightly different due to possible interactions between the solvent and solute molecules.
