Answer :
Final answer:
The molality of the solution is 0.461 mol/kg. The freezing point of the solution is 3.14°C. The boiling point of the solution is 81.27°C.
Explanation:
Molality:
Molality is defined as the amount of solute (in moles) per kilogram of solvent. First, we need to calculate the moles of naphthalene and benzene. The molar mass of naphthalene (C₁₀H₈) is 128.17 g/mol, so there are 0.0176 moles of naphthalene present. The molar mass of benzene (C₆H₆) is 78.11 g/mol, so there are 0.488 moles of benzene present. The mass of the solvent (benzene) is given as 38.1 g. Therefore, the molality of the solution is:
Molality = moles of solute / mass of solvent in kg
Molality = 0.0176 / 0.0381 = 0.461 mol/kg
Freezing Point:
The freezing point depression is a colligative property that depends on the molality of the solution. For pure benzene, the freezing point is 5.5°C. The freezing point depression (ΔTᶠ) can be calculated using the formula:
ΔTᶠ = Kᶠ * molality
where Kᶠ is the freezing point depression constant of the solvent. For benzene, the Kᶠ value is 5.12°C*kg/mol. Plugging in the values, we get:
ΔTᶠ = (5.12°C/mol) * 0.461 mol/kg = 2.36°C
Therefore, the freezing point of the solution is 5.5°C - 2.36°C = 3.14°C
Boiling Point:
The boiling point elevation is another colligative property that depends on the molality of the solution. For pure benzene, the boiling point is 80.1°C. The boiling point elevation (ΔTᵇ) can be calculated using the formula:
ΔTᵇ = Kᵇ * molality
where Kᵇ is the boiling point elevation constant of the solvent. For benzene, the Kᵇ value is 2.53°C*kg/mol. Plugging in the values, we get:
ΔTᵇ = (2.53°C/mol) * 0.461 mol/kg = 1.17°C
Therefore, the boiling point of the solution is 80.1°C + 1.17°C = 81.27°C
Learn more about Molality, Freezing Point, Boiling Point here:
https://brainly.com/question/11859871
#SPJ11
