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Relative lowering of vapour pressure and mole fraction of solute

This type of question, asked 9 times: 11 May 2023 S1, 11 May 2023 S2, 16 May 2023 S1, 16 May 2023 S2, 14 May 2024 S1, 21 Apr 2025 S2, 22 Apr 2025 S2, 16 Apr 2026 S1, 18 Apr 2026 S2. All 9 questions below, oldest first.

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  1. Question 1

    11 May 2023 S1

    62
    Vapour pressure of a pure solvent is 550 mm of Hg. By addition of a non-volatile solute it decreases to 510 mm of Hg. Calculate the mole fraction of solute in solution.

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  2. Question 2

    11 May 2023 S2

    55
    In a solution, mole fraction of solute is 0.2, when lowering in vapour pressure is 10 mm Hg. To get lowering of vapour pressure of 20 mm Hg, mole fraction of solute in solution is

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  3. Question 3

    16 May 2023 S1

    99
    Calculate the relative lowering of vapour pressure of solution containing 46 g of non-volatile solute in 162 g of water at 20°C20°C. [Molar mass of nonvolatile solute =46 g mol−1= 46\,\text{g mol}^{-1}]

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  4. Question 4

    16 May 2023 S2

    71
    Calculate the relative lowering of vapour pressure if vapour pressure of pure solvent and vapour pressure of solution at 25∘C25^\circ\text{C} are 32 and 30 mm Hg respectively.

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  5. Question 5

    14 May 2024 S1

    96
    Calculate the relative lowering of vapour pressure if the vapour pressure of benzene and vapour pressure of solution of non volatile solute in benzene are 640 mm Hg and 590 mm Hg respectively at same temperature.

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  6. Question 6

    21 Apr 2025 S2

    99
    Calculate the relative lowering of vapor pressure of solution containing 0.56 g nonvolatile solute in 100 g water [molar mass of solute =60 g mol−1= 60\text{ }g{\text{ }mol}^{- 1} ]

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  7. Question 7

    22 Apr 2025 S2

    65
    Calculate the relative lowering of vapour pressure of solution containing 3 g urea in 50 g water. [molar mass of urea =60 g mol−1= 60\text{ }g{\text{ }mol}^{- 1} ]

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  8. Question 8

    16 Apr 2026 S1

    24
    For a binary solution, when a nonvolatile nonelectrolyte solute is dissolved in solvent, the vapour pressure of solvent decreases by 20 % . what is mole fraction of solvent in solution ?

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  9. Question 9

    18 Apr 2026 S2

    22
    Calculate the mole fraction of solute in solution if vapour pressure of a solution and pure solvent are 27 mm Hg and 30 mm Hg respectively at 298 K.

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