Solutions, Colloids, Suspensions and Osmosis

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.In a solution, the substance that dissolves is called the:

   • A.solvent
   • B.solute✓ Correct Answer
   • C.precipitate
   • D.catalyst

   Explanation: The solute is the substance that dissolves, for example sugar in tea.

2. Q2.Which is called the universal solvent?

   • A.alcohol
   • B.water✓ Correct Answer
   • C.petrol
   • D.acetone

   Explanation: Water dissolves more substances than any other common liquid.

3. Q3.Milk is an example of a:

   • A.true solution
   • B.suspension
   • C.pure compound
   • D.colloid (emulsion)✓ Correct Answer

   Explanation: Fat droplets are dispersed in water.

4. Q4.The scattering of light by colloidal particles is called the:

   • A.Tyndall effect✓ Correct Answer
   • B.Doppler effect
   • C.Raman effect
   • D.photoelectric effect

   Explanation: A beam of light becomes visible in a colloid.

5. Q5.A solution of sugar in water is a:

   • A.suspension
   • B.true solution✓ Correct Answer
   • C.colloid
   • D.emulsion

   Explanation: Its particles are too small to scatter light.

6. Q6.Fog is a colloid in which:

   • A.solid is dispersed in a liquid
   • B.gas is dispersed in a solid
   • C.liquid is dispersed in a liquid
   • D.liquid droplets are dispersed in a gas✓ Correct Answer

   Explanation: Such a colloid is called an aerosol.

7. Q7.A saturated solution is one that:

   • A.has no solute
   • B.has no solvent
   • C.cannot dissolve more solute at that temperature✓ Correct Answer
   • D.is always coloured

   Explanation: Adding more solute leaves it undissolved.

8. Q8.The random zig-zag motion of colloidal particles is called:

   • A.Brownian motion✓ Correct Answer
   • B.Tyndall motion
   • C.osmosis
   • D.diffusion

   Explanation: It arises from collisions with solvent molecules.

9. Q9.Molarity is defined as the number of moles of solute per:

   • A.kilogram of solvent
   • B.gram of solute
   • C.litre of solvent
   • D.litre of solution✓ Correct Answer

   Explanation: Molality, by contrast, uses kilograms of solvent.

10. Q10.The size of particles in a colloid is roughly:

    • A.1 nm to 1000 nm✓ Correct Answer
    • B.less than 1 nm
    • C.more than 1 mm
    • D.exactly 1 cm

    Explanation: True solutions have smaller particles and suspensions larger ones.

11. Q11.Muddy water is an example of a:

    • A.true solution
    • B.colloid
    • C.alloy
    • D.suspension✓ Correct Answer

    Explanation: Its particles settle on standing.

12. Q12.Smoke is a colloid of:

    • A.gas in a liquid
    • B.liquid in a liquid
    • C.solid particles in a gas✓ Correct Answer
    • D.gas in a solid

    Explanation: It is an aerosol like fog.

13. Q13.An alloy is an example of a:

    • A.colloid
    • B.solid solution✓ Correct Answer
    • C.suspension
    • D.pure element

    Explanation: One metal is dissolved uniformly in another.

14. Q14.Dialysis separates:

    • A.dissolved small molecules from colloidal particles through a membrane✓ Correct Answer
    • B.solids from gases
    • C.oil from water
    • D.salt from sugar

    Explanation: It is the principle of the artificial kidney.

15. Q15.Soap cleans because it forms:

    • A.crystals with dirt
    • B.a gas with grease
    • C.micelles around grease✓ Correct Answer
    • D.a metal with dust

    Explanation: The oil-loving tails trap grease inside the micelle.

16. Q16.In a solution, the component present in the larger amount is usually the:

    • A.solute
    • B.precipitate
    • C.residue
    • D.solvent✓ Correct Answer

    Explanation: The solvent is the dissolving medium and the solute is dissolved in it.

17. Q17.Raoult's law deals with the:

    • A.lowering of vapour pressure of a solution✓ Correct Answer
    • B.rise of osmotic gas
    • C.colour of solutions
    • D.density of solids

    Explanation: A non-volatile solute lowers the vapour pressure of the solvent.

18. Q18.Osmosis is the movement of solvent molecules through a semipermeable membrane from:

    • A.higher to lower solute concentration
    • B.lower solute concentration to higher solute concentration✓ Correct Answer
    • C.a solid to a gas
    • D.cold to hot

    Explanation: Water moves toward the more concentrated solution.

19. Q19.Reverse osmosis, used in desalination, requires applying a pressure:

    • A.equal to zero
    • B.less than the osmotic pressure
    • C.greater than the osmotic pressure✓ Correct Answer
    • D.equal to atmospheric pressure only

    Explanation: This forces water out of the salt solution.

20. Q20.The solubility of gases in liquids generally:

    • A.increases as the temperature rises
    • B.is independent of temperature
    • C.decreases as the temperature rises✓ Correct Answer
    • D.is always zero

    Explanation: This is why warm water holds less dissolved oxygen.