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M12Post_LabAssignment_.docxName __________________________
Module 12
Post-Lab Assignment
Short Answer (30 points)
Answer the following questions based on material covered in this module.
(You must use complete sentences when answering each question.
1-point deduction per question not answered in complete sentences.)
1) What is the meaning of “analgesic.” Provide your reference. (5 points)
2) Why is the volume of the eluting solvent crucial? What limits are placed on the volume to be used? Explain. (5 points)
3) Why can we not use an ink pen or a marker when writing on the TLC plate? Explain. (5 points)
a) With the use of a ruler, determine the Rf value of the spot for Unknown B, following the procedure described. Show your calculations and watch your significant figures.
b) What does the Rf value of Unknown B tell you about the affinity of Unknown B to the mobile phase compared to the stationary phase? Be specific.
c) Why does A have two spots and B have only one? What conclusions can you draw about unknowns A and B? Be specific and explain.
A B
5) Based on the Rf values of the five analgesics we studied in the experiment, which analgesic is the most polar? Explain your rationale. (5 points)
