Consider the TLC chromatogram shown below This is the developed TLC plate obtained by a student after spotting three (3) different compounds in each lane and running the TLC using a 70:30 hexane:ethyl acetate mobile phase. Which of the following can help the student improve his/her TLC analysis? Select all that apply. (Note: ethyl acetate is more polar than hexane) A. Increase the polarity of the mobile phase to achieve better separation. B. Decrease the amount of hexane and increase the amount of ethyl acetate in the mobile phase. C. Use 100% hexane as the mobile phase to achieve better separation. D. Decrease the polarity of the mobile phase since the compounds are relatively non-polar. E. The compounds are impure. Further recrystallization is needed.

Consider the TLC chromatogram shown below This is the developed TLC plate obtained by a student after spotting three (3) different compounds in each lane and running the TLC using a 70:30 hexane:ethyl acetate mobile phase. Which of the following can help the student improve his/her TLC analysis? Select all that apply. (Note: ethyl acetate is more polar than hexane) A. Increase the polarity of the mobile phase to achieve better separation. B. Decrease the amount of hexane and increase the amount of ethyl acetate in the mobile phase. C. Use 100% hexane as the mobile phase to achieve better separation. D. Decrease the polarity of the mobile phase since the compounds are relatively non-polar. E. The compounds are impure. Further recrystallization is needed.

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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In normal phase TLC, the mobile phase is + polar than the stationary phase. Consider the TLC plate below, which was developed using a 25% ethyl acetate:hexane solution. If this same mixture of compounds was developed on a TLC using a 50% ethyl acetate:hexane solution, the orange spot would A mixture of two compounds was developed on a TLC plate. The result is shown below. What is one thing the chemist can do to get better results? In normal phase TLC, the mobile phase is : polar than the stationary phase. Consider the TLC plate below, which was c exane solution. If this same mixture of compounds was developed on a TLC using a 50% ethyl acetate:hexane solution, the orange spot would less sometimes more, sometimes less more A mixture of two compounds was developed on a TLC plate. The result is shown below. What is one thing the chemist can do to get better results?
See image below
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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…