Lowering of vapour pressure MCQ Basic Level

Lowering of vapour pressure MCQ Basic Level

Dear Readers,

Compared to other sections, Chemistry is considered to be the most scoring section. If prepared thoroughly, chemistry can help students to secure a meritorious position in the exam. These questions are very important in achieving your success in Exams after 12th.

Q1. For a solution of volatile liquids the partial vapour pressure of each component in solution is directly proportional to

•  Molarity
•  Mole fraction
•  Molality
•  Normality

Mole fraction

Q2. “The relative lowering of the vapour pressure is equal to the mole fraction of the solute.” This law is called

•  Henry's law
•  Raoult's law
•  Ostwald's law
•  Arrhenius's law

Raoult's law

Q3. The relative lowering of vapour pressure produced by dissolving 71.5 g of a substance in 1000 g of water is 0.00713. The molecular weight of the substance will be

•  18.0
•  342
•  60
•  180

180

Q4. When mercuric iodide is added to the aqueous solution of potassium iodide, the

•  Freezing point is raised
•  Freezing point is lowered
•  Freezing point does not change
•  Boiling point does not change

Freezing point is lowered

Q5. Vapour pressure of a solution is

•  Directly proportional to the mole fraction of the solvent
•  Inversely proportional to the mole fraction of the solute
•  Inversely proportional to the mole fraction of the solvent
•  Directly proportional to the mole fraction of the solute

Directly proportional to the mole fraction of the solvent

Q6. When a substance is dissolved in a solvent the vapour pressure of the solvent is decreased. This results in

•  An increase in the b.p. of the solution
•  A decrease in the b.p. of the solvent
•  The solution having a higher freezing point than the solvent
•  The solution having a lower osmotic pressure than the solvent

An increase in the b.p. of the solution

Q7. An aqueous solution of methanol in water has vapour pressure

•  Equal to that of water
•  Equal to that of methanol
•  More than that of water
•  Less than that of water

More than that of water

Q8. The pressure under which liquid and vapour can coexist at equilibrium is called the

•  Limiting vapour pressure
•  Real vapour pressure
•  Normal vapour pressure
•  Saturated vapour pressure

Real vapour pressure

Q9. The relative lowering of the vapour pressure is equal to the ratio between the number of

•  Solute moleules and solvent molecules
•  Solute molecules and the total molecules in the solution
•  Solvent molecules and the total molecules in the solution
•  Solvent molecules and the total number of ions of the solute

Solute molecules and the total molecules in the solution

Q10. At 300 K, when a solute is added to a solvent its vapour pressure over the mercury reduces from 50 mm to 45 mm. The value of mole fraction of solute will be

•  0.005
•  0.010
•  0.100
•  0.900

0.100