NEET UG - Purification techniques: crystallization sublimation distillation differential extraction chromatography and their applications Online Test (MCQ Quiz)

1. Which purification technique is most suitable for separating a volatile liquid from a non-volatile solid?

A) Crystallization B) Sublimation C) Distillation D) Chromatography

2. What is the principle behind crystallization as a purification technique?

A) Difference in boiling points B) Difference in solubility C) Difference in polarity D) Difference in molecular size

3. Which of the following compounds can be purified by sublimation?

A) Sodium chloride B) Benzoic acid C) Naphthalene D) Both B and C

4. Distillation is primarily used to separate liquids with significant differences in their:

A) Solubility B) Melting points C) Boiling points D) Density

5. Which type of distillation is used to separate liquids with very close boiling points?

A) Simple distillation B) Vacuum distillation C) Steam distillation D) Fractional distillation

6. Differential extraction relies on the difference in the ______ of the solute in two immiscible solvents.

A) Boiling points B) Solubility C) Melting points D) Viscosity

7. In chromatography, the stationary phase is:

A) The mobile liquid or gas B) The solid or liquid coated on a solid support C) The substance being separated D) The solvent used for elution

8. What is the mobile phase in paper chromatography?

A) The filter paper B) A solvent or mixture of solvents C) The ink being analyzed D) The absorbent layer

9. Which chromatographic technique is used to separate ions based on their charge and size?

A) Thin Layer Chromatography (TLC) B) Gas Chromatography (GC) C) Ion Exchange Chromatography D) Column Chromatography

10. Sublimation is a process where a solid directly converts into:

A) Liquid B) Gas C) Plasma D) A different solid

11. Which of the following is a common application of crystallization?

A) Separating isotopes B) Purifying solid organic compounds C) Analyzing gaseous mixtures D) Separating immiscible liquids

12. Steam distillation is particularly useful for purifying compounds that are:

A) Highly soluble in water B) Decomposable at their boiling points C) Non-volatile D) Ionic

13. In fractional distillation, the fractionating column provides a large surface area to facilitate:

A) Repeated vaporization and condensation B) Direct sublimation C) Differential extraction D) Ion exchange

14. Which chromatography technique uses a thin layer of adsorbent material coated on a glass plate?

A) Paper Chromatography B) Column Chromatography C) Thin Layer Chromatography (TLC) D) Gas Chromatography (GC)

15. What is the primary advantage of vacuum distillation?

A) To separate liquids with very close boiling points B) To purify compounds that decompose at their atmospheric boiling points C) To purify volatile solids D) To separate immiscible liquids

16. Which of the following is NOT a type of chromatography?

A) Adsorption Chromatography B) Partition Chromatography C) Distillation Chromatography D) Ion Exchange Chromatography

17. Differential extraction is most effective when the solute has a significantly different ______ in the two solvents.

A) Density B) Polarity C) Partition coefficient D) Molecular weight

18. In column chromatography, the stationary phase is typically a solid adsorbent packed into a tube. The mobile phase is:

A) A solid material B) A liquid or gas C) The mixture being separated D) The adsorbent itself

19. Which purification method is based on the principle of selective adsorption?

A) Distillation B) Crystallization C) Chromatography D) Sublimation

20. A compound that sublimes readily is likely to have:

A) Strong intermolecular forces B) Weak intermolecular forces C) High ionic character D) High molecular weight

21. Which technique is used to separate a mixture of liquids with boiling points differing by more than 25°C?

A) Fractional distillation B) Simple distillation C) Steam distillation D) Vacuum distillation

22. What is the purpose of the condenser in a distillation apparatus?

A) To heat the liquid B) To vaporize the liquid C) To cool the vapor and condense it back into liquid D) To collect the solid residue

23. Which type of chromatography is often used for analyzing volatile compounds at high temperatures?

A) Paper Chromatography B) Thin Layer Chromatography (TLC) C) Gas Chromatography (GC) D) Column Chromatography

24. Crystallization works best when the desired compound is ______ soluble at room temperature and ______ soluble at higher temperatures.

A) Highly; slightly B) Slightly; highly C) Equally; equally D) Insolubly; solubly

25. Which purification technique is used to isolate compounds that are insoluble in a particular solvent?

A) Distillation B) Filtration C) Sublimation D) Extraction

26. In chromatography, Rf value is defined as the ratio of the distance traveled by the:

A) Solvent front to the solute B) Solute to the solvent front C) Stationary phase to the solute D) Solute to the stationary phase

27. Differential extraction is particularly useful for separating a solute from a mixture when the solute has a higher solubility in:

A) The aqueous phase B) The organic phase C) Both phases equally D) Neither phase

28. Which of the following is a limitation of sublimation as a purification technique?

A) It requires a large amount of solvent. B) It is only suitable for liquids. C) Not all compounds sublime. D) It is very time-consuming.

29. The process of dissolving a solid in a suitable solvent, filtering, and then allowing crystals to form upon cooling is called:

A) Sublimation B) Distillation C) Crystallization D) Extraction

30. Which distillation technique is used to separate a volatile liquid from a non-volatile solid, or liquids with very large boiling point differences?

A) Fractional distillation B) Simple distillation C) Steam distillation D) Vacuum distillation

31. In Thin Layer Chromatography (TLC), the stationary phase is typically a thin layer of silica gel or alumina coated on a:

A) Paper B) Glass or plastic plate C) Metal foil D) Cotton cloth

32. Which purification technique is most suitable for separating components of a mixture based on their different affinities for the stationary and mobile phases?

A) Crystallization B) Distillation C) Sublimation D) Chromatography

33. When purifying a solid by crystallization, the ideal solvent should:

A) Dissolve the impurities well at all temperatures B) Dissolve the compound well at all temperatures C) Dissolve the compound sparingly at low temperatures and well at high temperatures D) Not dissolve the compound at any temperature

34. Which of the following methods is used to separate an organic acid from a mixture of neutral compounds and organic bases?

A) Sublimation B) Distillation C) Differential extraction D) Crystallization

35. Steam distillation is a type of distillation where the mixture is heated by passing steam through it. This is effective for compounds that are:

A) Miscible with water B) Insoluble in water and have a high boiling point C) Highly soluble in water D) Decomposable at high temperatures

36. In Gas Chromatography (GC), the separation of components is based on their differences in:

A) Boiling points and interaction with the stationary phase B) Solubility in a solvent C) Ability to sublime D) Density

37. Which of the following is a characteristic of the mobile phase in chromatography?

A) It is fixed in place. B) It moves through the stationary phase. C) It is the substance being separated. D) It is a solid adsorbent.

38. Filtration is a technique used to separate:

A) Dissolved solids from a liquid B) Solid particles from a liquid or gas C) Liquids with different boiling points D) Volatile solids from non-volatile solids

39. Which purification method is generally NOT suitable for purifying ionic compounds?

A) Crystallization B) Distillation C) Sublimation D) Differential extraction

40. What is the primary purpose of using a fractionating column in fractional distillation?

A) To increase the rate of vaporization B) To provide a large surface area for repeated condensation and vaporization C) To cool the vapors rapidly D) To collect the distillate directly

41. Which chromatography technique is often used for rapid qualitative analysis of reaction mixtures or purity checks?

A) Column Chromatography B) Gas Chromatography (GC) C) Thin Layer Chromatography (TLC) D) Ion Exchange Chromatography

42. A separatory funnel is used in which purification technique?

A) Crystallization B) Distillation C) Sublimation D) Differential extraction

43. Which purification technique is based on the difference in vapor pressure of components in a liquid mixture?

A) Crystallization B) Sublimation C) Distillation D) Chromatography

44. In partition chromatography, separation occurs based on the difference in the ______ of the solute between two immiscible liquid phases.

A) Boiling points B) Solubility C) Partition coefficient D) Density

45. Which of the following is a major advantage of chromatography over other purification techniques?

A) It can purify large quantities of material efficiently. B) It can separate complex mixtures with closely related components. C) It is always the fastest method. D) It requires no solvent.

46. What is the 'tailing' phenomenon in chromatography?

A) The solvent front moving too quickly B) The solute forming a sharp, defined spot C) The solute spreading out into a long streak D) The stationary phase degrading

47. Which technique is used to purify heat-sensitive compounds by reducing the boiling point under reduced pressure?

A) Simple distillation B) Fractional distillation C) Steam distillation D) Vacuum distillation

48. Crystallization is generally most effective for purifying:

A) Gases B) Liquids with high boiling points C) Solid organic compounds D) Ionic compounds

49. In differential extraction, the solvent that extracts the solute more efficiently is known as the:

A) Stationary phase B) Mobile phase C) Extracting solvent D) Aqueous phase

50. Which property is NOT typically exploited for separation in chromatography?

A) Polarity B) Volatility C) Solubility D) Boiling point

Purification techniques: crystallization sublimation distillation differential extraction chromatography and their applications - Online Test

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