Chromatographic Techniques: TLC & GC MCQs

Chromatographic Techniques – TLC & GC MCQs

Chromatographic techniques like Thin Layer Chromatography (TLC) and Gas Chromatography (GC) are essential for separating and analyzing chemical mixtures. TLC is a quick, cost-effective method using a stationary phase on a plate, while GC is highly precise, utilizing a gas carrier for volatile compounds. Explore key MCQs on TLC & GC to enhance your understanding of these powerful analytical techniques.

Fundamentals of Chromatography

1. Chromatography is primarily used for:
   (a) Synthesizing chemical compounds
   (b) Separating components in a mixture
   (c) Determining the boiling point of substances
   (d) Measuring electrical conductivity
   Show Answer Answer: (b) Separating components in a mixture

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2. In chromatography, the stationary phase refers to:
   (a) The solvent moving through the system
   (b) The fixed phase where separation occurs
   (c) The mobile phase carrying the analyte
   (d) The gas used in gas chromatography
   Show Answer Answer: (b) The fixed phase where separation occurs

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Thin Layer Chromatography (TLC)

3. What is the stationary phase in Thin Layer Chromatography (TLC)?
   (a) A liquid solvent
   (b) A thin layer of silica gel or alumina
   (c) A gas
   (d) A metal plate
   Show Answer Answer: (b) A thin layer of silica gel or alumina

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4. Which factor affects the separation of components in TLC?
   (a) Particle size of the stationary phase
   (b) Type of mobile phase solvent
   (c) Polarity of analytes
   (d) All of the above
   Show Answer Answer: (d) All of the above

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5. The retention factor (R_f) in TLC is calculated as:
   (a) Distance traveled by the analyte ÷ Distance traveled by the solvent
   (b) Distance traveled by the solvent ÷ Distance traveled by the analyte
   (c) Time taken for separation ÷ Distance traveled
   (d) None of the above
   Show Answer Answer: (a) Distance traveled by the analyte ÷ Distance traveled by the solvent

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6. Which method is commonly used to visualize colorless spots in TLC?
   (a) UV light exposure
   (b) Heating in a furnace
   (c) Immersion in water
   (d) Weighing the plate before and after separation
   Show Answer Answer: (a) UV light exposure

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Gas Chromatography (GC)

7. Gas Chromatography (GC) is mainly used for:
   (a) Separating volatile compounds
   (b) Analyzing metals
   (c) Measuring pH values
   (d) Identifying proteins
   Show Answer Answer: (a) Separating volatile compounds

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8. In GC, the mobile phase is always:
   (a) A solid
   (b) A liquid
   (c) A gas
   (d) A polymer
   Show Answer Answer: (c) A gas

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9. Which of the following gases is commonly used as the carrier gas in GC?
   (a) Oxygen
   (b) Nitrogen
   (c) Carbon dioxide
   (d) Sulfur dioxide
   Show Answer Answer: (b) Nitrogen

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10. Which detector is commonly used in Gas Chromatography?
    (a) UV-Vis detector
    (b) Flame Ionization Detector (FID)
    (c) Atomic Absorption Spectrometer (AAS)
    (d) NMR detector
    Show Answer Answer: (b) Flame Ionization Detector (FID)

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11. The efficiency of separation in GC depends on:
    (a) Column length
    (b) Temperature programming
    (c) Flow rate of carrier gas
    (d) All of the above
    Show Answer Answer: (d) All of the above

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