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Gas Chromatography MCQ Questions & Answers

Gas Chromatography MCQs : This section focuses on the "Gas Chromatography". These Multiple Choice Questions (MCQs) should be practiced to improve the Gas Chromatography skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

Slow injection of large samples leads to band broadening and loss of resolution.

A. True
B. False

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Question 2

What are the benefits of decreasing the column internal diameter?

A. Increased sample capacity
B. Increased resolution
C. Reduced risk of column overloading
D. All of the above

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Question 3

Theoretical plates are used to

A. estimate the efficiency of a column
B. determine the thickness of the stationary phase
C. measure the distribution of the analyte between mobile and stationary phases
D. None of the above

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Question 4

Derivatisation of a sample is carried out to

A. reduce polarity of the analytes
B. increase the detector response
C. increase volatility of the analytes
D. all of the above

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Question 5

Helium is generally preferred as carrier gas over nitrogen and hydrogen because

A. it is inert
B. it has a lower viscosity
C. it doubles up as a party gas for balloons and funny voices
D. all of above

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Question 6

The GC trace obtained after an experiment is called a

A. chromatograph
B. chromatogram
C. chromatophore
D. graph

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Question 7

What useful information can be found from a Van Deemter plot?

A. The selectivity factor
B. Optimum mobile phase flow rate
C. Optimum column temperature
D. Optimum column length

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Question 8

For the separation of which of the following substances, Gas-solid chromatography is being used?

A. Thermally stable organic components
B. Volatile organic components
C. Thermally stable inorganic components
D. Low molecular weight gaseous species

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Question 9

What is the typical internal diameter of fused silica capillary columns?

A. 0.2-0.3 mm
B. 0.3-0.5mm
C. 0.5-1.0 mm
D. 1.0-2.0 mm

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Question 10

Sample injection port must be maintained at a temperature at which rapid vapourisation occurs but thermal degradation does not occur.

A. True
B. False

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Question 11

Which of the following detectors give mass flow-dependent signals?

A. Electron capture detector
B. Field ionisation detector
C. Thermal conductivity detector
D. All of the above

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Question 12

Doubling the column's length increases resolution by a factor of

A. (2)0.5
B. 2
C. 3
D. 4

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Question 13

Which of the following detectors give concentration-dependent signals?

A. Electron-capture detector
B. Thermal conductivity
C. Infra-red detector
D. All of these

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Question 14

Which of the following is the disadvantage of helium, which can be used as carrier gas in gas chromatography?

A. Dangerous to use
B. Expensive
C. Reduced sensitivity
D. High density

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Question 15

Capillary columns are open tubular columns constructed from which of the following materials?

A. Glass
B. Metal
C. Stainless steel
D. Fused silica

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Question 16

Split injection is carried out by

A. splitting the sample into smaller portions to inject sequentially
B. splitting the sample into smaller portions to inject at the same time through parallel ports
C. splitting off some of the sample so that it does not enter the column
D. none of the above

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Question 17

A retention gap is placed between the injector and the front of the column to

A. retain contaminants and prevent them from reaching the column
B. retain the sample and release it gradually to the column
C. prevent backflush of the injected solution
D. all of the above

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Question 18

Flame ionisation detector is also known as Katharometer.

A. True
B. False

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Question 19

Which of the following are not used as stationary phases in a GC column?

A. Polysiloxanes
B. Silica
C. Cyclodextrins
D. None are used as stationary phases

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Question 20

In which of the following methods are liquid samples injected into the column in gas chromatography?

A. Gas tight syringe
B. Micro-syringe
C. Rotary sample valve
D. Solid injection syringes

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Question 21

Which of the following is the disadvantage of hydrogen, which can be used as carrier gas in gas chromatography?

A. Dangerous to use
B. Expensive
C. Reduced sensitivity
D. High density

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Question 22

Which of the following is the disadvantage of nitrogen, which can be used as carrier gas in gas chromatography?

A. Dangerous to use
B. Expensive
C. Reduced sensitivity
D. High density

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Question 23

Which of the statements is correct?

A. Gas chromatography is used to analyse gases
B. Gas chromatography is used to analyse solids
C. Gas chromatography is used to analyse gases, solutions and solids
D. All of the above

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Question 24

Which of the following is the commonly used support material for the packed column in gas chromatography?

A. Glass
B. Metal
C. Diatomaceous earth
D. Stainless steel

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Question 25

Which of the following is not used for detection in GC?

A. Infrared spectroscopy
B. NMR
C. Flame ionisation
D. Electrical conductivity

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Question 26

Resolution is proportional to the

A. number of theoretical plates in a column
B. square root of the number of theoretical plates in a column
C. square of the number of theoretical plates in a column
D. cube root of the number of theoretical plates in a column

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Question 27

What does the retention factor, k', describe?

A. The distribution of an analyte between the stationary and the mobile phase
B. The migration rate of an analyte through a column
C. The velocity of the mobile phase
D. All of these

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Question 28

Sample injection is considered successful if

A. all of the sample in the injector has been added to the column
B. the sample is concentrated at the start of the column
C. the sample is spread evenly along the column
D. the sample is homogenously spread along the column

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Question 29

Column bleeding occurs when

A. elution of the analyte is extended over time
B. the column is cracked and stationary phase leaks out
C. traces of the stationary phase are eluted
D. the column breaks during installation and causes personal injury

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Question 30

The column is heated to

A. prevent analyte condensation within the column
B. control elution of the different analytes
C. reduce band broadening to get sharper peaks
D. all of these

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Question 31

Which of the following is not a desirable feature of the ovens used in gas chromatography?

A. It must have a fast rate of heating
B. Power consumption should be kept low
C. It must have maximum thermal gradients
D. It should have proper insulation

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Question 32

Which of the following is not a type of detector used in gas chromatography?

A. Argon ionisation detector
B. Thermal conductivity detector
C. UV visible spectrometric detector
D. Electron capture detector

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Question 33

Which of the following is not an ideal characteristic of a detector used in gas chromatography?

A. Linear response to the solutes
B. Short response time
C. High reliability
D. Sensitive to the changes in the flow rate of a carrier gas

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Question 34

Which of the following is not a feature of carrier gas used in gas chromatography?

A. It must be chemically inert
B. It should be suitable for the detector employed
C. It should not be completely pure
D. It should be cheap

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Question 35

Which of the following is the advantage of a straight packed column?

A. It can be packed uniformly
B. It can be repacked easily
C. It is compact
D. It is easier to heat it evenly

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Question 36

Which of these effects result from slow injection of a large sample volume?

A. Increased resolution
B. Decreased resolution
C. Non-linear detector response
D. Constant resolution

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Question 37

Which of the following is the disadvantage of coiled or helical shaped packed chromatographic column?

A. It cannot be packed uniformly
B. It cannot be repacked easily
C. It is not compact
D. It is not easy to heat it evenly

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Question 38

Sample retention in the column is measured by

A. retention time
B. retention factor
C. retention index
D. all of these

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Question 39

What does the selectivity factor describe?

A. The proportional difference in widths of two chromatographic peaks
B. The maximum number of different species which a column can separate simultaneously
C. The relative separation achieved between two species
D. None of the above

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Question 40

Headspace analysis is carried out in order to

A. analyse volatile compounds from solid or liquid samples
B. determine the psychological state of the tutor
C. analyse the column contents ahead of the sample
D. determine non-volatiles

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Question 41

What must be done to the solid samples for it to be introduced into the column without using solid injection syringes in gas chromatography?

A. Introduced in hot-zone of the column
B. Dissolved in volatile liquids
C. Introduced using rotary sample valve
D. Introduced using sampling loops

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Question 42

Which of the following gases is unsuitable for use as a GC carrier gas?

A. Nitrogen
B. Helium
C. Oxygen
D. All of the above

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Question 43

In column switching chromatography

A. compounds trapped on one column are eluted to another column
B. one column is removed and replaced by another
C. the flow to the column is switched on and off repeatedly
D. any of the above

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