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NEET-UG and JEE Main Chemistry · Class 12

Relative lowering of vapour pressure — NEET & JEE Questions

Relative lowering of vapour pressure is a topic in Solutions, a Class 12 Chemistry chapter of the NEET-UG and JEE Main syllabus. TestBudy holds 12 published NEET-UG and JEE Main questions on Relative lowering of vapour pressure, each with the marking scheme of the real paper.

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Relative lowering of vapour pressure MCQs with solutions

10 of the 12 published questions on this topic, exactly as they appear in a test. Answers and worked solutions come with your result rather than on this page.

  1. Question 1 · difficulty L1 · recall

    For a dilute solution of a non-volatile solute, the relative lowering of vapour pressure is equal to the mole fraction of

    • A. the solute
    • B. the solvent
    • C. the vapour
    • D. the container gas

  2. Question 2 · difficulty L2 · understanding

    Raoult's law for a solution containing a non-volatile solute is written as

    • A. p=xsolventp0p=x_{solvent}p^0
    • B. p=xsolutep0p=x_{solute}p^0
    • C. p=p0/xsolventp=p^0/x_{solvent}
    • D. p=p0+xsolutep=p^0+x_{solute}

  3. Question 3 · difficulty L2 · understanding

    Adding a non-volatile solute to a volatile solvent generally

    • A. lowers the solvent vapour pressure
    • B. raises the solvent vapour pressure
    • C. leaves vapour pressure unchanged
    • D. makes vapour pressure infinite

  4. Question 4 · difficulty L2 · understanding

    Relative lowering of vapour pressure is a colligative property because it depends mainly on

    • A. the number of solute particles
    • B. the colour of the solute
    • C. the chemical identity of the solvent only
    • D. the shape of the container

  5. Question 5 · difficulty L3 · application

    A solution has solvent mole fraction 0.90. What is the relative lowering of vapour pressure?

    • A. 0.10
    • B. 0.90
    • C. 1.00
    • D. 9.0

  6. Question 6 · difficulty L3 · application

    The vapour pressure of a pure solvent is 100 mmHg and that of its solution is 95 mmHg. What is the relative lowering of vapour pressure?

    • A. 0.05
    • B. 0.95
    • C. 5
    • D. 95

  7. Question 7 · difficulty L3 · application

    If the mole fraction of a non-volatile solute is 0.02 and the pure solvent vapour pressure is 200 mmHg, what is the solution vapour pressure?

    • A. 196 mmHg
    • B. 4 mmHg
    • C. 200 mmHg
    • D. 204 mmHg

  8. Question 8 · difficulty L3 · application

    A solution has relative lowering of vapour pressure 0.01. What is the solute mole fraction for a non-volatile solute?

    • A. 0.01
    • B. 0.99
    • C. 1.01
    • D. 100

  9. Question 9 · difficulty L4 · application

    One mole of a non-volatile solute is dissolved in 99 mol of solvent. What is the relative lowering of vapour pressure?

    • A. 0.01
    • B. 0.99
    • C. 1.00
    • D. 0.10

  10. Question 10 · difficulty L4 · application

    Two solutions contain equal moles of solvent. Solution P has twice as many moles of a non-volatile solute as Q, both dilute. Which has the larger relative lowering of vapour pressure?

    • A. P
    • B. Q
    • C. They are equal
    • D. Neither lowers vapour pressure

Common mistakes in Relative lowering of vapour pressure

Recorded against questions in this topic that are not shown above, so none of these points at an answer you can see on this page.

  • Ignores particle multiplication from dissociation.
  • Uses the solute mole fraction to compute solvent vapour pressure.

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