Engineering Chemistry MCQ (Thin Layer Chromatography)

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Engineering Chemistry MCQ (Thin Layer Chromatography)

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1. The principle on which thin layer chromatography is based is that the ____________
a) Different compounds are absorbed on an absorbent to different degrees
b) Different compounds are absorbed on an absorbent to same degrees
c) Different compounds are adsorbed on an adsorbent to different degrees
d) Different compounds are absorbed on an absorbent to same degrees
Answer: c
Explanation: Thin layer chromatography is based on the fact that different
compounds are adsorbed on an adsorbent to different degrees. It is a
chromatography technique used to separate non-volatile mixtures.

2. The size of a thin layer of adsorbent is about ____________
a) 0.1 mm
b) 0.2 mm
c) 0.3 mm
d) 0.4 mm
Answer: b
Explanation: The size of a thin layer of adsorbent is about 0.2 mm. TLC plates are
usually commercially available, with standard particle size ranges to improve reproducibility

3. The chromaplate or thin layer chromatography plate is made up of ____________
a) Glass
b) Wood
c) Fibre
d) Metal
Answer: a
Explanation: The chromaplate or thin layer chromatography plate is made up of
glass. TLC plates are usually commercially available, with standard particle size
ranges to improve reproducibility. They are prepared by mixing the adsorbent, such
as silica gel, with a small amount of inert binder like calcium sulfate (gypsum) and water.

4. The eluant filled in the closed jar is ____________
a) Mixture of gases
b) Mixture of a liquid and a gas
c) Mixture of solids
d) Mixture of liquids
Answer: d
Explanation: The eluant filled in the closed jar is liquid or mixture of liquids.

5. Select the incorrect statement from the following options.
a) The spots of colorless compounds are invisible to the eyes
b) These spots can be detected by putting the plate under ultraviolet light
c) These spots can be detected by placing the plate in a covered jar containing iodine crystals
d) None of the mentioned
Answer: d
Explanation: All the mentioned options are correct. The spots of colorless
compounds are invisible to the eyes, can be detected by putting the plate under
ultraviolet light and can be detected by placing the plate in a covered jar containing iodine crystals.

6. The relative adsorption of each component of the mixture is expressed in terms of its ____________
a) Acceleration factor
b) Retardation factor
c) Both acceleration and retardation factor
d) None of the mentioned
Answer: b
Explanation: The relative adsorption of each component of the mixture is expressed in terms of its retardation factor (Rf).

7. Select the correct statement from the following.
a) Paper chromatography is a type of partition chromatography
b) A special quality paper is used in paper chromatography
c) Chromatography paper contains water trapped in it, which acts as stationary phase
d) All of the mentioned
Answer: d
Explanation: Paper chromatography is a type of partition chromatography. A special
quality paper is used in paper chromatography which contains water trapped in it, which acts as a stationary phase.

8. Amino acids detected by spraying the plate with ninhydrin solution is an example of ____________
a) Column chromatography
b) Thin layer chromatography
c) Paper chromatography
d) Liquid chromatography
Answer: c
Explanation: Amino acids detected by spraying the plate with a ninhydrin solution is
an example of paper chromatography. Paper chromatography is an analytical method that is used to separate colored chemicals or substances.

9. Paper chromatography is based on continuous differential partitioning of components of a mixture between stationary and mobile phases.
a) True
b) False
Answer: a
Explanation: Paper chromatography is based on a continuous differential
partitioning of components of a mixture between stationary and mobile phases. It is
an analytical method that is used to separate colored chemicals or substances.

10. Retardation factor is the ratio of ____________
a) Distance moved by substance from base line to distance moved by the solvent from base line
b) Distance moved by solvent from base line to distance moved by the substance from base line
c) Distance moved by substance from top line to distance moved by the solvent from top line
d) Distance moved by solvent from top line to distance moved by the substance from top line
Answer: a
Explanation: Retardation factor is the ratio of the distance moved by substance
from base line to distance moved by the solvent from base line.