Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure, in bar of a mixture of 26.0 g of heptane and 35.0 g of octane?

Solution

Answer:
We have given,

Molar mass of heptane,
C₇H₁₆ = 100 g mol^–1Molar mass of octane,
C₈H₁₈ = 114 g mol^–1Moles of heptane

$= \frac{Wt . of heptane}{Mol . mass of heptane}$

$= \frac{26}{100} = 0.26$

Similarly, Moles of octane

$= \frac{35}{114} = 0.31$

Mole fraction heptane

$= \frac{n_{A}}{n_{A} + n_{B}}$

$= \frac{0.26}{0.26 + 0.31} = 0.456$

Mole fraction of octane

$= \frac{0.31}{0.26 + 0.31} = 0.543$

Partial vapour pressure = Mole fraction x Vap.
Pressure of pure component.
Partial vapour pressure of heptane

= 0.456 x 105.2 = 47.97 kPa

Partial vapour pressure of octane
= 0.543 x 46.8 = 25.4 kPa

Total vapour pressure of solution = 73.08 kPa.

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Solutions

Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure, in bar of a mixture of 26.0 g of heptane and 35.0 g of octane?

Some More Questions From Solutions Chapter

Calculate the osmotic pressure in pascals exerted by a solution prepared by dissolving 1.0 g of polymer of molar mass 185,000 in 450 mL at 37⁰C.

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For Daily Free Study Material Join wiredfaculty

Solutions

Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure, in bar of a mixture of 26.0 g of heptane and 35.0 g of octane?

Some More Questions From Solutions Chapter

Calculate the osmotic pressure in pascals exerted by a solution prepared by dissolving 1.0 g of polymer of molar mass 185,000 in 450 mL at 370C.

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Calculate the osmotic pressure in pascals exerted by a solution prepared by dissolving 1.0 g of polymer of molar mass 185,000 in 450 mL at 37⁰C.