A student was given an unknown compound dissolved in acetone. The student decided to identify the compound by TLC. The student decides to use a 1:1 hexanes/acetone solvent system. Once the TLC plate was finished running, the student pulls out the TLC to look at it under UV. The student’s partner remarks that all the spots had not moved. What would be best for the two students to try next? A) Try to test a 1:9 hexanes/acetone solvent system. B)Try to test a 9:1 hexanes/acetone solvent system. C)Try to test a 9:1 hexanes/acetone solvent system and a 1:9 hexanes/acetone solvent system.. D)Redo the TLC plate; it was the students technique that caused the problem. E) The compound cannot be identified by TLC

A student was given an unknown compound dissolved in acetone. The student decided to identify the compound by TLC. The student decides to use a 1:1 hexanes/acetone solvent system. Once the TLC plate was finished running, the student pulls out the TLC to look at it under UV. The student’s partner remarks that all the spots had not moved. What would be best for the two students to try next? A) Try to test a 1:9 hexanes/acetone solvent system. B)Try to test a 9:1 hexanes/acetone solvent system. C)Try to test a 9:1 hexanes/acetone solvent system and a 1:9 hexanes/acetone solvent system.. D)Redo the TLC plate; it was the students technique that caused the problem. E) The compound cannot be identified by TLC

EBK A SMALL SCALE APPROACH TO ORGANIC L

4th Edition

ISBN:9781305446021

Author:Lampman

Publisher:Lampman

Chapter89: Thin-layer Chromatography

Section: Chapter Questions

Problem 1P

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The following are the uses of TLC except Choices: Determine the number of components in a sample Detect a given compound or compounds in a very crude mixture Determine the concentration of certain components of the mixture Find suitable conditions prior to running a column chromatogram None of the above
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You decided to check the purity of your product by TLC. You spotted salicylic acid (lane 1), your crude synthetic aspirin (lane 2) and a sample of pure aspirin (lane 3). After elution, draw a picture of what developed TLC plate (UV visualization) would look like?
Based on TLC, how can you tell if the reaction is complete and what is the relevvance of the multiple marks in the lanes of the tlc? PROCEDURE To a six inch test tube was added thiamine hydrochloride (0.65 g), followed by water (2mL). The mixture was gently shaken until homogeneous, and then ethanol (7.5 mL)was added. Finally, sodium hydroxide (10%, 1.5 mL) was added and the mixture wasgently stirred to ensure complete mixing.Benzaldehyde (3.8 mL) was then added at room temperature in one portion with gentlestirring. The pH of the resulting reaction mixture was determined and adjusted to >10by dropwise addition of 10% sodium hydroxide. The reaction mixture was then partiallysubmerged in a 65 °C water bath2 and the progress of the reaction was periodicallymonitored by TLC analysis.Once TLC analysis indicated that the reaction was complete, the reaction mixture wascooled to approximately room temperature, and then chilled in an ice-water bath. Theresulting precipitate was collected by…
Use the following scenario and results to answer the following four questions: Scenario: It was suspected that a particular drug sample contained three components: X, Y and Z. To check this, the mixture was analyzed by TLC with a nonpolar developing solvent on silica gel. The following TLC plate was obtained. Which components are most likely to be present in the sample? X and Z Y only Y and Z Y and another unknown component X and Y
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A student spots an unknown sample on a TLC plate and develops it in pentane solvent. Only one spot, for which the Rf value is 0.05, is observed. Is the un-known material a pure compound? What can be done to verify the purity of the sample?
A TLC analysis is performed on both crude and purified biphenyl. Upon visualization under the UV- lamp both spots remain at the baseline. This is likely because: a. Biphenyl is a polar molecule and therefore should remain at the baseline upon TLC plate development in the proper eluent. b. The samples were not spotted properly on the TLC plate. c. The solvent was too non-polar. d. The solvent was too polar. e. The solvent evaporated before the TLC plate could be added to the chamber.