5. Here, you can find an example of a paper chromatography experiment. Use the two Chromatograms below the answer the questions that follow: a) (3p) What are the components of unknown sample (X)? b) (12p) Calculate the Rf values for A, B, C in the first chromatogram. d) (10p) When using the 20% Acetone in Water, are the substances strongly attracted to the stationary phase or the mobile Phase? Briefly explain your reasoning. e) (10p) Which substance does show strongest affinity to the stationary phase in the first chromatogram. Briefly explain your reasoning. wwan wwww www 50 80% Acetone in water 20% Acetone in water Finish line 50 45 45 40 40 35 35 30 30 25 20 15 10 10 Starting line A B C D X A B C D X

5. Here, you can find an example of a paper chromatography experiment. Use the two Chromatograms below the answer the questions that follow: a) (3p) What are the components of unknown sample (X)? b) (12p) Calculate the Rf values for A, B, C in the first chromatogram. d) (10p) When using the 20% Acetone in Water, are the substances strongly attracted to the stationary phase or the mobile Phase? Briefly explain your reasoning. e) (10p) Which substance does show strongest affinity to the stationary phase in the first chromatogram. Briefly explain your reasoning. wwan wwww www 50 80% Acetone in water 20% Acetone in water Finish line 50 45 45 40 40 35 35 30 30 25 20 15 10 10 Starting line A B C D X A B C D X

EBK A SMALL SCALE APPROACH TO ORGANIC L

4th Edition

ISBN:9781305446021

Author:Lampman

Publisher:Lampman

Chapter88: Column Chromatography

Section: Chapter Questions

Problem 4P

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Similar questions

In an experiment of Reverse Phase chromatography using C-18 stationary phase and a mixture of methanol/ethyl acetate/acetic acid, a researcher tried to separate the 3 compounds shown below. Which compound would have the lowest Rf and which the highest Rf in this experiment? Explain your answer and show any relevant structures.
Qno1: why there is a need of chromatography and chromatography thecniqs. B) when and where we should use normal and reverse phase chromatography
A student places an unknown sample on a thin-layer chromatography plate and develops it in dichloromethane as a solvent. Only one spot whose Rf is 0.98 is observed. Does this result indicate that the unknown material is a pure compound? If not a pure compound, suggest an alternate procedure to verify the purity of the sample.
How does the chromatogram change when methanol:water (90:10) is used as the mobile phase compared to a 100% methanol run?
1) When you try separating an unknown mixture by normal-phase liquid chromatography with 50% hexane and 50% methyl t-butyl ether, the peaks are too close together. (not resolved) Should you use a higher or lower concentration of hexane in the next run?
Look up the structures of naphthalene and benzoic acid and determine their polarities. Using the polarity of the molecules, predict which would elute first and which would elute second on a C18 column in reverse phase chromatography.
Three students did a chromatography experiment, where Rf = distance of solute / distance of solvent. What could be the possible errors why student 3 had results that are quite far from that of students A and B?
In another chromatography experiment, pure chemical “A” leaves a yellow spot with an Rf = 0.49 and pure chemical “B” leaves a red spot with an Rf = 0 .68. An unknown mixture when chromatographed is found to contain two components, a blue spot (Rf = 0.49) and a yellow spot (Rf = 0.66). Does the unknown mixture contain any of the known pure chemicals’ “A” or “B”?