Read Here: 100+ MCQs on Chromatography
1. Answer: b
Explanation: Chromatography is a physical method that is used to separate complex mixtures. The mixture of different components is flushed through the system at different rates.
2. Answer: a
Explanation: In Column chromatography, the stationary phase held in a narrow tube and the mobile phase is forced through it under pressure. It is carried out in a long glass column having a stop-cock near the bottom.
3. Answer: a
Explanation: In chromatography, there are two phases namely, stationary phase and mobile phase. The stationary phase can be solid or a liquid supported on a solid.
4. Answer: b
Explanation: In chromatography, the mobile phase can be composed of liquid or gas. It cannot be a solid material.
5. Answer: d
Explanation: The given options are all examples of adsorbents in Column adsorption except potassium permanganate. Some other adsorbents are starch and chromatographic purified siliceous earth.
6. Answer: c
Explanation: Thin layer chromatography involves the separation of substances of a mixture over a 0.2mm thick layer (thin layer) of an adsorbent. The adsorbent can be silica gel or alumina.
7. Answer: a
Explanation: In Column chromatography, the stationary phase is made of solid and the mobile phase is made of liquid. It is carried out in a long glass column which has a stop-cock near the bottom.
8. Answer: a
Explanation: In Thin layer chromatography, the stationary phase is made of solid and the mobile phase is made of liquid.
9. Answer: c
Explanation: In Radial paper chromatography, the mobile phase moves horizontally over a circular sheet of paper. Separation takes place based on partition.
10. Answer: c
Explanation: Liquid chromatography can be performed either in columns or on plane surfaces. It could be liquid-solid chromatography or liquid-liquid chromatography.
11. Answer: a
Explanation: Gas chromatography can be performed only in columns. It could be gas-solid chromatography or gas-liquid chromatography.
12. Answer: c
Explanation: In Gas-liquid phase chromatography, the stationary phase is made of liquid and the mobile phase is made of gas. Separation is based on partition.
13. Answer: d
Explanation: In Planar Chromatography, the stationary phase is supported on a flat plate of paper. The mobile phase moves by the influence of gravity or capillary action.
14. Answer: b
Explanation: The operation that occurs after the injection of feed is a separation in the column. After that, elution from the column and detection of components takes place.
15. Answer: b
Explanation: During the elution phase, different components elute at different times. Components with least affinity elute first.
16. Answer: a
Explanation: Chromatogram is a detector that responds to concentration solute and is placed at the end of the column. The position of peaks on the time axis can be used to determine components of the sample.
17. Answer: b
Explanation: Chromatogram is a detector that responds to concentration solute and is placed at the end of the column. The area under the peak can be used to determine the amount of component in the sample.
18. Answer: c
Explanation: Y will elute from the column first. Components with least affinity to the stationary phase will elute first.
19. Answer: c
Explanation: Using Chromatogram as a detector in Chromatography, a graph is obtained between concentration and time. The detector is placed at the bottom of the column.
20. Answer: c
Explanation: In older analytical methods, gravity facilitated the movement of the mobile phase. The effect of capillary action was also employed to allow movement.
21. Answer: d
Explanation: The unmarked component is detector. It is placed at the bottom of the column. It responds to solute concentration.
22. Answer: a
Explanation: In chromatography, molar concentration of solute in stationary phase is directly proportional to molar concentration of solute in mobile phase.
Cs α Cm
Cs = k Cm
‘k’ is the distribution constant.
23. Answer: c
Explanation:
Cs α Cm
Cs = k Cm
If k=1, it denotes that the solute is equally distributed in the mobile and stationary phase.
24. Answer: d
Explanation: The time taken by the analyte after sample injection to reach the detector is called retention time. The retention of a solute in the system can be used to identify the solute.
25. Answer: a
Explanation: The time required for a molecule of the mobile phase to pass through the column is called dead time. The effectiveness of the system depends on dead time.
26. Answer: c
Explanation: Adjusted retention time is the remaining retention time after subtracting dead time from retention time. It affects the effectiveness of the system.
27. Answer: b
Explanation: Retention volume is the volume of mobile phase required to make a solute band move from the point of injection through the column to the detector.
28. Answer: c
Explanation: Adjusted retention volume is the remaining retention volume after subtracting dead volume from retention volume.
Vadjusted retention = Vretention – Vdead
29. Answer: c
Explanation: Retention factor is defined as the ratio of moles of solute in stationary phase to the moles of solute in the mobile phase. It is used for determining the migration rates of solutes in the column.
30. Answer: d
Explanation: Total porosity is the ratio of the interstitial volume of packing to the volume of its total mass. In a capillary column, total porosity is 1.
31. Answer: b
Explanation: Average linear rate of mobile migration is the ratio of the length of column packing to dead time. It influences the effectiveness of the column in separating solutes.
32. Answer: a
Explanation: Average linear rate of solute migration is the ratio of a length of column packing to retention time. It influences the effectiveness of the column in separating solutes.
33. Answer: b
Explanation: Retention volume can be obtained by finding the product of retention time and volumetric flow rate.
Flow rate = Cross section of empty column × Average linear velocity × Total porosity
34. Answer: c
Explanation: Selectivity factor/ Relative retention must always be greater than 1. It is also known as Relative migration rate.
35. Answer: c
Explanation: Plate height is the distance that the solute moves while undergoing one partition. It is expressed in length.
36. Answer: a
Explanation: The efficiency of the column increases when the plate number becomes greater and the plate height becomes smaller. Column efficiency greatly depends on plate height and plate number.
37. Answer: a
Explanation: Eddy diffusion is given as, A = λ dp. It is also called multipath term.
38. Answer: b
Explanation: Longitudinal diffusion is given as, B = 2 γ DM.It is also called axial diffusion.
39. Answer: c
Explanation: In gas-liquid chromatography, when films are used in the interior of the capillary column the value of Eddy diffusion (A) is zero. To minimize A, diameter of packing should be small and uniform.
40. Answer: c
Explanation: For an unpacked coated capillary column, the value of the obstruction factor is 1. For a packed column, the value is 0.6.
41. Answer: d
Explanation: Base line resolution is achieved when degree of resolution/separation is 1.5. The baseline bandwidths of adjacent bands are almost constant.
42. Answer: c
Explanation: The expression for plate number, N is given as N = (4tR/Wb)2. It is a dimensionless quantity.
43. Answer: d
Explanation: Gas-solid chromatography is used for the separation of low molecular weight gaseous species. Its application is limited because of semi-permanent retention of the analyte.
44. Answer: c
Explanation: It should be highly pure. Further, it should be readily available and non-inflammable.
45. Answer: a
Explanation: Hydrogen is dangerous to use. It has better thermal conductivity and lower density.
46. Answer: b
Explanation: Helium is expensive. Its advantages are that it has low density and it allows greater flow rates.
47. Answer: c
Explanation: Nitrogen has reduced sensitivity. It is still one of the commonly used carrier gas in gas chromatography.
48. Answer: b
Explanation: Liquid samples injected into the column in gas chromatography using micro-syringe. Syringes of various capacities are available.
49. Answer: b
Explanation: Solid samples must be dissolved in volatile liquids for introducing it into the column. They can be introduced directly using solid injection syringes.
50. Answer: c
Explanation: Diatomaceous earth is the commonly used support material for the packed column in gas chromatography. The columns could be made of glass or metal.
51. Answer: c
Explanation: The advantage of the straight column is that it can be repacked easily. It is not compact in size.
52. Answer: b
Explanation: The disadvantage of coiled or helical shaped packed chromatographic column is that it cannot be repacked easily. It is compact in size and can easily be heated in an even manner.
53. Answer: d
Explanation: Capillary columns are constructed using fused silica. It is a very high purity glass.
54. Answer: c
Explanation: The ovens used in gas chromatography must have maximum thermal gradients. The temperature must be uniform over the whole column.
55. Answer: d
Explanation: The unmarked component is syringe. Hence, the answer is sample injection system. It is for the introduction of sample into the flowing gas stream.
56. Answer: d
Explanation: The detector used in gas chromatography must be insensitive to the changes in flow rate of carrier gas. There are many detectors used in gas chromatography.
57. Answer: c
Explanation: UV visible spectrometric detector is not used in gas chromatography. It is used in liquid chromatography.
58. Answer: c
Explanation: Flame ionization detector has high sensitivity to all organic compounds. It is the commonly used detector for gas chromatography.
59. Answer: b
Explanation: Thermal conductivity detector has relatively low density when compared to other detectors used in gas chromatography. It is based on the principle that all gases conduct heat in varying degrees.
60. Answer: d
Explanation: Electron capture detector is used to detect environmental samples like polychlorinated biphenyls and chlorinated pesticides. It is highly sensitive to molecules containing functional groups such as halogen and phosphorous.
61. Answer: a
Explanation: In Sulphur chemiluminescence detector, the eluent is mixed with hydrogen and burned and then mixed with ozone and its intensity is measured. The resultant is a measure of sulphur compounds present.
62. Answer: a
Explanation: Flame photometric detector is primarily responsive to volatile sulphur or phosphorous compounds. It is also responsive to tin and nitrogen.
63. Answer: c
Explanation: Photo ionization detector uses ultraviolet radiation from lamps to produce ionisation of solute molecules. The current produced is measured and recorded.
64. Answer: b
Explanation: Thermionic emission detector used in gas chromatography is most sensitive to phosphorous. It is 500 times more sensitive to phosphorous than Flame ionization detector.
65. Answer: b
Explanation: Thermionic emission detector has a non-volatile bead of rubidium silicate placed above the flame tip. It is maintained at about 180V with respect to the collector.
66. Answer: a
Explanation: In Argon ionisation detector, the carrier gas is excited by a radioactive source and the atoms of carrier gas are excited to a metastable state. It uses argon as carrier gas.
67. Answer: c
Explanation: Graphite is not used as a heating element in Thermal conductivity detector. Platinum, gold and tungsten wire are used as heating elements.
68. Answer: d
Explanation: The unmarked component is Radioactive β- emitter. Nitrogen and hydrogen are the best carrier gases for these detectors.
69. Answer: b
Explanation: Gas-solid chromatography is based on the adsorption of gaseous substances on a solid surface. It is useful for the separation of rare gases.
70. Answer: b
Explanation: Hydrogen sulphide cannot be retained by gas-liquid columns. It can be separated using gas-solid chromatography.
71. Answer: c
Explanation: Gas-solid chromatography leads to semi-permanent retention of the analyte. Hence, it is used for limited applications.
72. Answer: a
Explanation: Open tubular column can be used in Gas-solid chromatography. Analytical/separation column and guard column is used in liquid chromatography.
73. Answer: a
Explanation: Wide bore capillary has a shorter retention time. It is an advantage. It is undesirable to have a longer retention time.
74. Answer: b
Explanation: The lifetime of gas-solid chromatography is long. It can be used for geometrical isomers.
75. Answer: a
Explanation: Molecular sieves are a special adsorbent used in gas-solid chromatography. It is used in open tubular columns.
76. Answer: d
Explanation: Molecular sieves have the ability to distinguish materials on the basis of their size. This property can be used in separating molecules of linear structure from bulky ones.
77. Answer: a
Explanation: The disadvantage of reciprocating pump used in liquid chromatography is that it produces pulsed flow. Therefore, the flow must be damped before it affects the column.
78. Answer: a
Explanation: Pneumatic pumps provide pulse free output. They are inexpensive.
79. Answer: d
Explanation: Pulse dampers are used to avoid variations in flow. They must have minimal dead volume.
80. Answer: d
Explanation: Reduction in sample size and reduction in column diameter will improve the efficiency of the separation process in liquid chromatography. The effect of uneven flow will also be reduced.
81. Answer: c
Explanation: The practical problems that arise due to a decrease in column diameter are the requirement of small particle size and high pressure drop. But, it increases column efficiency.
82. Answer: c
Explanation: Guard column removes particles that cause precipitation upon contact with stationary or mobile phase. It is placed before the separation column.
83. Answer: d
Explanation: Capillary column is used in gas chromatography. Analytical column is also known as a separation column.
84. Answer: d
Explanation: Paper chromatography is not a column-type chromatography. It makes use of strips of hollow cylinders of filter paper.
85. Answer: a
Explanation: Radial compression columns have a wider diameter than the standard separation column. The cartridges used are of low cost.
86. Answer: d
Explanation: Detector response time increases in narrow bore columns. High purity solvents must be used in these columns.
87. Answer: c
Explanation: In Affinity chromatography, immobilized biochemical is used as stationary phase. It is used to separate one or few solutes from hundreds of unretained solutes.
88. Answer: b
Explanation: In High pressure liquid chromatography (HPLC), samples need to be vaporised. It has high sensitivity.
89. Answer: d
Explanation: The limitation of Syringe type pump is that it has a limited solvent capacity and is inconvenient when solvents are to be changed.
90. Answer: a
Explanation: Solvent programming is done to provide equal bandwidths. It provides maximum sensitivity for every solute in the sample.
91. Answer: a
Explanation: Flexible bellows or compressible gas passed through tee columns take up some of the pulsation energy which is released to provide smooth pressure without pulsations. Its main purpose is to avoid pulses.
92. Answer: b
Explanation: In syringe pumps, maintenance is infrequent. However, it has high pressure capability.
93. Answer: d
Explanation: Syringe pumps used in High pressure liquid chromatography are most suitable for small bore columns. It is the most commonly used piston type pump.
94. Answer: d
Explanation: Solvent pumps have to be used to reduce pulses in a solvent flow. When there is a pulsed flow, the efficiency of column decreases.
95. Answer: a
Explanation: Hydraulic capacitance flow control system used in HPLC is irrespective of the solvent viscosity. It is also irrespective of the solvent compressibility.
96. Answer: c
Explanation: Bulk property detectors respond only to bulk properties of the mobile phase. It does not respond to properties of solutes.
97. Answer: d
Explanation: The volume of the detector must be small. If the volume of the detector is large it may lead to band broadening.
98. Answer: c
Explanation: Scanning wavelength detector provides a real time spectrum of the component of interest. UV visible detector is the most widely used detection system.
99. Answer: c
Explanation: Refractive index detectors depend on Snell’s law at the interface between the cell wall and the flowing liquid to deflect the light beam. Changes in refractive index are monitored by a position sensor.
100. Answer: d
Explanation: Refractive index detectors used in liquid chromatography are not dependent on absorption. It depends on reflection, refraction and interference.
101. Answer: b
Explanation: Fluorescence detectors can be used for detection of amino acids in protein hydrolyzates by introducing the reagent dansylchloride in the sample. Other compounds that can be detected are petroleum products and natural products.
102. Answer: a
Explanation: In Adsorption detector used in liquid chromatography, the reference cell is packed with inactive glass beads. The other detector cavity is packed with silica, alumina or porous glass beads.
103. Answer: a
Explanation: Laser detectors used in liquid chromatography cause thermal distortion and have decreased sensitivity. This is because of the high energies of a laser.
104. Answer: d
Explanation: Another name for the thermal detector is micro-adsorption detector. The operation depends upon temperature changes taking place due to the heat of adsorption.
105. Answer: c
Explanation: The cells in UV-Visible detectors are made of quartz, KELF and Teflon. They are not made of silica.106. Answer: c
Explanation: Refractive index type detectors have low volume flow rates. It is one of the major advantages of the refractive index type of detectors.
107. Answer: b
Explanation: Combining RI and UV detectors almost any component can be detected. In some cases, single detection system may give incorrect results.
108. Answer: d
Explanation: The part that is not marked is quartz window. This detector is used to detect components that absorb any wavelength in the UV-Visible region.
109. Answer: c
Explanation: When ion exchange chromatography is used for amino-acid analysis, high accuracy is obtained. It is inconvenient to handle many individual samples and cleaning of glassware is laborious.
110. Answer: d
Explanation: Resin column chromatography is the most suitable for amino-acid analysis. Here, ion exchange resin chromatography is followed.
111. Answer: d
Explanation: Ninhydrin is the colour reagent used in resin column chromatography. The colour reaction occurs during a known period and controlled temperature.
112. Answer: a
Explanation: Proline and hydroxyproline are measured at 440nm. All the other amino acids are measured at 570nm.
113. Answer: d
Explanation: In Automatic amino-acid analyzer, the sample having 0.05 to 2 µmoles of each amino compound is introduced at the top of the ion exchange column. Buffer is then supplied to the column.
114. Answer: d
Explanation: Components which are ninhydrin negative cannot be analysed using resin column chromatography. Only the components that are nindydrin positive are analysed using this method.
115. Answer: b
Explanation: De-aerator is used to eliminate trapper air in pumps of an automatic amino-acid analyzer. Here, bubble-trap type de-aerator is used.
116. Answer: b
Explanation: Gas chromatography cannot be used for proteins or polypeptides. Further, accuracy is lost while converting amino-acids into the gaseous phase.
