0 votes, 0 avg 72 Created by Sana KaussarChromatographic Techniques Quiz Part 1 (batch 07) 1 / 30If peak tailing occurs in a GC chromatogram, what could be the possible reason? 1) Poor injection technique 2) Overloading of the column 3) Contaminated stationary phase 4) all 2 / 30Which of the following gases is commonly used as a carrier gas in GC 1) He 2) CO2 3) O2 4) H2 3 / 30Which of the following factors does NOT affect the Rf value in paper chromatography 1) Type of paper used 2) Temperature 3) Distance traveled by the solvent 4) Initial concentration of the solute 4 / 30What is the mobile phase in paper chromatography 1) The filter paper 2) sample 3) solvent 4) filter paper 5 / 30Why is a reference sample often used in paper chromatography 1) To verify the purity of the solvent 2) To provide a basis for comparison with unknown samples 3) To clean the paper before use 4) To prevent the solvent from evaporating too quickly 6 / 30What type of detector is best suited for detecting halogenated compounds in GC 1) Thermal conductivity detector (TCD) 2) Electron capture detector (ECD) 3) Flame ionization detector (FID) 4) UV detector 7 / 30Discoverer of chromatography 1) michael tswett 2) Henry Richard 3) walliam watson 4) John crick 8 / 30What type of compounds are best analyzed using Gas Chromatography? 1) Volatile and thermally stable compounds 2) high molecular weight compounds 3) Strongly polar ionic compounds 4) Insoluble solids 9 / 30What is the purpose of spraying the chromatogram with ninhydrin in amino acid analysis? 1) To visualize colorless amino acids 2) To dissolve the sample completely 3) To increase the Rf values 4) To make the paper more absorbent 10 / 30What is the role of a "developing chamber" in paper chromatography 1) To heat the sample for faster separation 2) To maintain a saturated atmosphere of solvent vapors 3) To provide an electric field for separation 4) To dissolve the sample before it moves 11 / 30What does a higher Rf value indicate in TLC 1) Stronger interaction with the stationary phase 2) Weaker interaction with the stationary phase 3) Higher molecular weight of the compound 4) Increased retention time 12 / 30In paper chromatography, what is the primary force that helps separate components 1) Gravity 2) Capillary action 3) Centrifugal force 4) Electromagnetic force 13 / 30The separation of compounds in TLC is based on 1) Differences in molecular weight 2) Differences in adsorption affinity 3) Differences in melting point 4) Differences in boiling point 14 / 30What is the primary reason for using a mixture of solvents in the mobile phase 1) To increase the speed of separation 2) To dissolve different components with varying polarities 3) To decrease the Rf values of all compounds 4) To prevent the paper from dissolving 15 / 30Which of the following solvents would likely move a polar compound faster in paper chromatography 1) Water 2) ethanol 3) hexane 4) acetone 16 / 30The separation of components in GC is primarily based on differences in 1) molecular weight 2) solubility 3) boiling point 4) UV absorbance 17 / 30In a two-dimensional paper chromatography setup, why is the paper rotated 90° before the second run 1) To improve separation of overlapping spots 2) To increase the Rf values 3) To ensure all compounds move to the same position 4) To dry the paper before re-running the experiment 18 / 30What is the advantage of using TLC over column chromatography? 1) TLC is faster and requires less solvent 2) TLC can handle large sample volumes 3) TLC gives better resolution 4) TLC is more suitable for large-scale purification 19 / 30Which of the following statements about paper chromatography is FALSE 1) It is a type of partition chromatography 2) The stationary phase is solid 3) The mobile phase is usually a liquid solvent 4) The separation occurs due to differences in solubility and adsorption 20 / 30Locating reagent used for phonols is 1) ninhydrin 2) 10% H2SO4 3) FeCl3 4) chromate solution 21 / 30The retention time of a compound in GC depends on 1) Column temperature 2) Flow rate of carrier gas 3) Polarity of the stationary phase 4) all 22 / 30What is the formula for calculating the Rf value 1) Distance traveled by solvent / Distance traveled by solute 2) Distance traveled by solute / Distance traveled by solvent 3) Distance traveled by solute × Distance traveled by solvent 4) Distance traveled by solvent – Distance traveled by solute 23 / 30Why is pencil used instead of ink to draw the baseline in paper chromatography? 1) Pencil marks do not dissolve in the solvent 2) Pencil marks are easier to erase 3) Pencil reacts with the solvent 4) Ink improves the separation process 24 / 30Which solvent system would be most appropriate for separating nonpolar compounds in TLC? 1) ethanol 2) acetone 3) acetic acid 4) hexane 25 / 30The stationary phase in Gas Chromatography is typically 1) A solid adsorbent 2) A liquid coated on a solid support 3) A metal surface 4) a gas 26 / 30What is the mobile phase in Gas Chromatography (GC) 1) Liquid solvent 2) Inert gas 3) Solid adsorbent 4) High-pressure liquid 27 / 30If a compound does not move from the baseline in TLC, what could be the reason 1) The compound is highly polar and strongly adsorbed to the stationary phase 2) The solvent is too polar 3) The compound is volatile and evaporated 4) The TLC plate was overheated 28 / 30Commonly used detector in GC is 1) FID 2) UV visible 3) Refractive index 4) all 29 / 30. What is the effect of increasing the column temperature in GC 1) Decreases retention time 2) Increases retention time 3) Increases peak broadening 4) Does not affect separation 30 / 30What is the role of a guard column in GC 1) To separate compounds 2) To protect the analytical column from contaminants 3) To increase retention time 4) to cool the sample Your score isThe average score is 71% 0% Restart quiz
Click here to Join