n normal phase chromatography, the stationary phase is silica gel or alumina, in
ID: 1034644 • Letter: N
Question
n normal phase chromatography, the stationary phase is silica gel or alumina, in reverse phase chromatography the stationary phase used is typically non-polar C-18 (hydrocarbon) com the mobile phase includes water and methanol. Compound Adderall DTBZ Catechol Retention time (Min.) 2.99 1.05 4.32 13. Col umn chromatography was used to separate the three compounds shown above and the were as given in the table. Which of the following was the most likely stationary phase and phased used to obtain the above results? Methanol/Water Mobile Phase, C18-compound column B. Methanol/Water Mobile Phase, Silica column Hexane/Ethyl Acetate Mobile Phase, C18-compound column Hexane/Ethyl Acetate Mobile Phase, Silica column Methanol/Water Mobile Phase, Alumina column 14. Consider the melting points of the four compounds in the table below. A chemist o unknown sample that was one of the four compounds in the table. He performed t experiment in order to determine the identity of the compound. First, he mixed th with trans-cinnamic acid and found the melting point of that mixture to be 129 ° mixed the unknown with aspirin and found the melting point of that mixture to b Lastly, he mixed the unknown with urea and found the melting point of that mix 133 °C. Based on the mixed melting point analysis.... Compound trans-cinnamic acid133 urea aspirin benzamide Melting point, oC 134 135 127 A. The unknown is probably trans-cinnamic acid B. The unknown is probably urea C. The unknown is probably aspirin D. The unknown is probably benzamide E. It is impossible to know the identity of the solidExplanation / Answer
13. The three compounds are separated using the column and solvent,
A.
Since the non-polar component DTBZ has the lowest retention time, it stayed on the column the longest. Staiiobary phase is non-polar.
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14. The unknown is probably,
B. urea
as the melting point did not change when mixed with unknown.
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