MCQ Test on Gas Chromatography
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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
2.
2. 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
3. 3. 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
4. 4. 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
5. 5. 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
6. 6. Slow
injection of large samples leads to band broadening and loss of resolution.
a) True
b) False
7. 7. 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
8. 8. 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
9.
9. 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
10 10.
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
11 11.
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
12 12.
Capillary
columns are open tubular columns constructed from which of the following materials?
a) Glass
b) Metal
c) Stainless steel
d) Fused silica
13 13.
Sample
injection port must be maintained at a temperature at which rapid vapourisation
occurs but thermal degradation does not occur.
a) True
b) False
14 14.
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
15. Derivatization is done in G.C (GATE
2002)
a) to
convert a less polar compound to a more polar compound
b) to
make the compound non-volatile
c) to
convert a polar compound to less polar compound
d) to
liquefy a solid
16. Gas chromatography techniques can
be used for (GATE 1998)
a) Qualitative
analysis only
b) Quantitative
analysis only
c) Both
A and B
d) None
of these
17. One of the following conditions is maintained in programmed temperature gas chromatography (GATE 2001)
a) temperature
of the whole column is raised during analysis
b) temperature
at the sample injection system is raised
c) temperature
at the detector is gradually raised
d) temperature
at the recorder alone is raised
18. In gas chromatography, derivatization is desirable to (GATE 2007)
(A)
improve the thermal stability of compounds
(B)
enable interaction with carrier gas
(C)
introduce a detector-oriented tag into the molecule
(D)
remove contaminants
Identify
the correct statements.
a) A,B
b) B,C
c) A,
C
d) A,D
19. In gas chromatography, the basis for separation of the components of the volatile material is the difference in
a) partition
coefficients
b) conductivity
c) molecular
weight
d) molarity
20.
Gas chromatography can be performed in which of the following ways?
a)
Only in columns
b)
Only on plane surfaces
c)
Either in columns or on plane surfaces
d)
Neither in columns nor on plane surfaces
21.
In Gas-liquid phase chromatography, the stationary phase is composed of
_________ and the mobile phase is made of _________
a)
Solid, liquid
b)
Liquid, liquid
c)
Liquid, gas
d)
Solid, gas
22. Which of the following is not
used for detection in GC?
a) Infrared
spectroscopy
b) NMR
c) Flame
ionisation
d) Electrical
conductivity
23.
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
24.
The GC trace obtained after an experiment is called a
a) chromatograph
b) chromatogram
c) chromatophore
d) graph
a) Nitrogen
b) Helium
c) Oxygen
d) All
of the above
26. 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
27. 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
28. Resolution is proportional to the
a) a) number of theoretical plates in a column
b) b) square root of the number of theoretical
plates in a column
c) c) square of the number of theoretical
plates in a column
d) d) cube root of the number of theoretical
plates in a column
a
29.
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
30.
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
31.
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
32.
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
33.
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
34.
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
35.
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
36.
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
a) Increased
sample capacity
b) Increased
resolution
c) Reduced
risk of column overloading
d) All of the above
38. Sample retention in the column is measured by
a) retention
time
b) retention
factor
c) retention
index
d) all
of these
39.
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
a) Polysiloxanes
b) Silica
c) Cyclodextrins
d) None
are used as stationary phases
a a) all of the sample in the injector has
been added to the column
b) b) the sample is concentrated at the start
of the column
c) c) the sample is spread evenly along the
column
d d) the sample is homogenously spread along
the column
|
1.
d |
2.
c |
3.
a |
4.
b |
5.
c |
6.
a |
7.
b |
|
8.
b |
9.
c |
10.
c |
11.
b |
12.
d |
13.
a |
14.
c |
|
15.
a |
16.
c |
17.
a |
18.
c |
19.
a |
20.
a |
21. c |
|
22.
b |
23.
b |
24.
b |
25.
c |
26.
b |
27.
a |
28.
b |
|
29.
d |
30.
d |
31.
a |
32.
c |
33.
a |
34.
c |
35.
d |
|
36.
d |
37.
b |
38.
d |
39.
c |
40.
b |
41.
b |
42. |
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