COLLOIDAL STATE MCQs

1. What happens in the process of electrosmosis?

(A) Positively charged colloidal particles move, but negatively charged particles remain stationary

(B) Both, colloidal particles and dispersion medium move

(C) Colloidal particles move towards the electrodes

(D) Only dispersion medium moves to carry the current

2. Which one of the following can act as disperse phase of the colloidal system?

(A) Solid

(B) Liquid

(C) All of A, B, and C

(D) Gas

3. A system is considered to be in the suspension state if the particle size of the dispersed phase is:

100 nm’)”> (A) < 100 nm

100 nm’)”> (B) > 100 nm

100 nm’)”> (C) > 100 micrometer

100 nm’)”> (D) > 100 Å

4. Which colligative property can be helpful and used to characterize colloidal particles?

(A) Lowering in vapor pressure

(B) Depression in freezing point

(C) Osmotic pressure

(D) Elevation in boiling point

5. Colloids can be purified by which one of the following?

(A) Dialysis

(B) Coagulation

(C) The Breeding arc method

(D) Peptization

6. The process of removing dissolved impurities from a colloidal system, by means of diffusion through a suitable membrane under the influence of an electric field, is called:

(A) Electrosmosis

(B) Peptization

(C) Electrophoresis

(D) Electrodialysis

7. The migration of positively charged colloidal particles, under an electrical field, towards the cathode is called:

(A) Cataphoresis

(B) Electrosmosis

(C) Sedimentation

(D) Electrodialysis

8. Smoke is a dispersion of:

(A) Liquid in gas

(B) Solid in gas

(C) Gas in solid

(D) Gas in gas

9. Which electrolyte will be most effective in the coagulation of arsenious sulphide sol?

(A) MgSO4

(B) AIPO4

(C) NaNO3

(D) K4[Fe(CN)6]

10. In emulsions, what are the dispersed phase and the dispersion medium?

(A) Both solids

(B) Both gases

(C) Both liquids

(D) Phase is liquid and medium is solid

11. In a lyophobic sol, the stability of the dispersed phase results from:

(A) Liking for the dispersion medium

(B) The surface tension of the medium

(C) The formation of an electrical layer between the two phases

(D) The viscosity of the medium

12. A silver iodide sol was prepared by mixing KI and AgNO₃ solutions with the AgNO₃ in slight excess. Which description is true regarding its sol particles?

(A) Negatively charged because of the excess of NO₃⁻ ions

(B) Neutral

(C) Negatively charged because I⁻ ions are adsorbed from the KI solution

(D) Positively charged because of the excess of Ag⁺ ions in the AgI lattice

13. An emulsifier is an agent which can:

(A) Stabilizes an emulsion

(B) Homogenizes an emulsion

(C) Causes coagulation of an emulsion

(D) Helps in the formation of an emulsion

14. When a strong beam of light is passed through a colloidal solution, the light will:

(A) Reflected

(B) Scattered

(C) Dispersed

(D) Pass unchanged

15. ____ is a colloidal system in which a liquid is dispersed in a solid.

(A) Gel

(B) Sol

(C) Emulsion

(D) Precipitate

16. The gold numbers of some hydrophilic substances are Gelatin 0.005–0.01, Egg albumen 0.08–0.10, Gum Arabic 0.10–0.15, Soluble starch 10–15. Which of these will act ideally as a protective colloid?

(A) Gum Arabic

(B) Gelatin

(C) Soluble starch

(D) Egg albumen

17. Which can act as a protective colloid?

(A) Oil-in-water emulsion

(B) Silica gel

(C) Gelatin

(D) All three

18. Which will be most effective in the coagulation of Fe(OH)₃ sol?

(A) Mg₃(PO₄)₂

(B) MgSO₄

(C) AlCl₃

(D) NaCl

19. The process of passing of a precipitate into colloidal solution, on adding an electrolyte, is called

(A) Dialysis

(B) Peptization

(C) Electrophoresis

(D) Electrosmosis

20. The Tyndall effect was helpful and used by Zsigmondy to devise

(A) The ultracentrifuge

(B) Electrodialysis

(C) The osmometer

(D) The ultramicroscope

21. The arsenic’s colloidal solution prefers to absorb

(A) K⁺

(B) S²⁻

(C) NO₃⁻

(D) H⁺

22. A system is considered to be in the colloidal state if the particle size of the dispersed phase ranges from

(A) 1 to 10 Å

(B) 10 to 1000 Å

(C) 10 to 100 Å

(D) 0.5 to 1 Å

23. The Tyndall effect is not observed in

(A) True solutions

(B) Suspensions

(C) Colloidal solutions

(D) Emulsions

24. When a freshly formed precipitate of stannic oxide is peptised by a small amount of sodium hydroxide, the colloidal particles may be described as

(A) [SnO₂] Sn⁴⁺ : OH

(B) [SnO₂] SnO₂²⁻ : 2Na⁺

(C) [SnO₂] Sn⁴⁺ : O²⁻

(D) [SnO₂] Na⁺ : OH⁻

25. Which statement is not true regarding the Stern theory of charge on colloidal particles?

(A) In the immediate vicinity of the colloidal particles there is an excess of counter ions

(B) The greater the concentration and charge of ions in the diffused electrical double layer, the larger is the thickness of the layer

(C) The colloidal particle has a charge distribution at its surface

(D) At large distance from the colloidal particles, the concentrations of co-ions and counter-ions are almost equal

26. Which substances is an example of colloidal state?

(A) All of A, B, and C

(B) Milk

(C) Blood

(D) Fog

27. In ice cream/solid foam, which is/are the dispersed phase and the dispersion medium?

(A) Phase is gas and medium is solid

(B) Both liquids

(C) Both gases

(D) Both solids

28. In curd/jelly, Which is/are the dispersed phase and the dispersion medium?

(A) Phase is liquid and medium is solid

(B) Both liquids

(C) Both gases

(D) Both solids

29. In clouds/fog/mist, the dispersed phase and the dispersion medium are

(A) Both solids

(B) Phase a liquid and medium in gas

(C) Both liquids

(D) Both gases

30. In milk/oil in water, Which is/are the dispersed phase and the dispersion medium?

(A) Both solids

(B) Phase is liquid and medium in solid

(C) Both gases

(D) Both liquids

31. Which methods is/are helpful and used in the preparation of colloids?

(A) Reduction

(B) All of A, B, and C

(C) Hydrolysis

(D) Oxidation

32. In ruby/gem, Which is/are the dispersed phase and the dispersion medium?

(A) Both solids

(B) Both liquids

(C) Both gases

(D) Phase is liquid and medium is solid

33. Which factors is/are responsible for the development of charge on colloids?

(A) All of A, B, and C

(B) Dissociation of surface molecules

(C) Preferential adsorption of ions

(D) Presence of acidic or basic group

34. _______is a colloidal system in which both the dispersion phase and dispersed phase are liquid.

(A) Smoke

(B) Whipped cream

(C) Emulsion

(D) Mist

35. Which statement is not true with regard to lyophobic sols?

(A) They are normally stable

(B) These are normally inorganic materials

(C) Surface tension is similar to dispersion medium

(D) Particles carry some charge

36. According to Hardy-Schulze law, What is the precipitation power of the electrolytes for negative sol?

Mg²⁺ > Na⁺’)”> (A) Na⁺ > Mg²⁺ > Al³⁺

Mg²⁺ > Na⁺’)”> (B) Al³⁺ > Mg²⁺ > Na⁺

Mg²⁺ > Na⁺’)”> (C) Na⁺ > Al⁴⁺ > Mg²⁺

Mg²⁺ > Na⁺’)”> (D) Mg²⁺ = Mg²⁺ > Al³⁺

37. Which parameters are/is helpful and used to express the protective action of sols?

(A) Gold number

(B) All of A, B, and C

(C) Rubin number

(D) Iron number

38. The minimum concentration of the electrolyte needed to bring coagulation of the sols is called_________.

(A) Gold number

(B) Iron number

(C) Rubin number

(D) Precipitation value

39. Which statement is not true with regard to lyophilic sols?

(A) These are normally organic materials

(B) Surface tension is lower to dispersion medium

(C) They are normally unstable

(D) Particles may have little/no charge

40. At critical micelle concentration (CMC), the surface molecules

(A) Decompose

(B) Dissociate

(C) Associate

(D) Become soluble

41. Which statement is not true?

(A) Lyophobic sols are reversible

(B) More electrolyte is needed to precipitate lyophilic sols in comparison

(C) Lyophilic sols have higher viscosity than that the medium

(D) Particles of lyophilic sols are highly hydrated

42. What is the precipitation value of NaCl for negative sol?

(A) 0.65

(B) 51

(C) 0.325

(D) 0.093

43. Which protective colloids has large value of gold number?

(A) Gelatin

(B) Albumin

(C) Hemoglobin

(D) Starch

44. Which protective colloid has small value of gold number?

(A) Starch

(B) Albumin

(C) Hemoglobin

(D) Gelatin

45. Emulsifying agent in milk is

(A) Fat

(B) Protein casein

(C) Enzymes

(D) Lactic acid

46. Blood and blood clot are the colloidal state parlance, respectively

(A) Emulsion, sol, gel

(B) Gel, sol, emulsion

(C) Emulsion, gel; sol

(D) Aerosols, sol, gel

47. Which act as associated colloids?

(A) Substances like colloids only at higher concentration

(B) Substances like colloids only at lower temperature

(C) Aggregates of colloids with diameter less than 1 cm

(D) None of A, B, and C

48. Which technique is helpful and used to separate proteins from salts?

(A) Diffusion

(B) Dialysis

(C) Osmosis

(D) Transportation

49. Milk may be kept fresh by incorporating a few drops of

(A) Formaldehyde

(B) Formic acid

(C) Acetic acid

(D) Acetaldehyde

50. As₂O₃ sol is

(A) Negatively charged

(B) Neutral

(C) Positively charged

(D) None of A, B, and C

51. According to Hardy-Schulze law, what is the precipitation power of the electrolytes for positive sol?

Sulfate > Chloride’)”> (A) Chloride > Sulfate > Phosphate

Sulfate > Chloride’)”> (B) Phosphate > Sulfate > Chloride

Sulfate > Chloride’)”> (C) Chloride = Sulfate = Phosphate

Sulfate > Chloride’)”> (D) Chloride > Phosphate > Sulfate

52. Colloidal sulfur is prepared by the reaction of following

(A) H₂SO₄ and H₂S₂O₈

(B) I₂ and Na₂S₂O₃

(C) FeCl₃ and H₂S

(D) FeCl₂ and Na₂S

53. Tyndall effect is more pronounced in which of the following?

(A) Lyophobic sol

(B) Lyophilic sol

(C) Starch solution

(D) Foam

54. A sol has a very low osmotic pressure because of

(A) Its association

(B) Large size of the particles

(C) Its dissociation

(D) Its charge

55. Which is an example of associated colloids?

(A) Rubber and benzene

(B) Protein and water

(C) As₂O₃ sol

(D) Soap and water

56. Which is a hydrophilic colloidal solution?

(A) Arsenic sulfide

(B) Starch sol

(C) Barium sulfate solution

(D) Silver iodide sol

57. At the isoelectric point

(A) The pH of the sol becomes 7

(B) None of A, B, and C

(C) Sol becomes electrically neutral

(D) Sol coagulates

58. Which is true for lyophilic sols?

(A) Irreversible in nature

(B) Formed by inorganic substances

(C) Readily coagulated by the addition of electrolytes

(D) They are self-stabilized

59. Which is a heteropolar sol?

(A) Rubber in toluene

(B) Sulfur in water

(C) Protein in water

(D) Starch in water

60. To which does pumice stone belong?

(A) Gel

(B) Emulsion

(C) Aerosol

(D) Foam