MCAT Organic Chemistry Review 2018-2019

(singke) #1

Questions 4 and 5 refer to the following table:


Compound Retardation    Factor  in  Ether
Benzyl alcohol 0.10
Benzyl acetate 0.26
p-Nitrophenol 0.23
1-Naphthalenemethanol 0.40

4 . What    would   be  the effect  on  the Rf  values  if  thin-layer  chromatography  (TLC)   were    run
with hexane rather than ether as the eluent?

(A)  No effect
(B) Increase tenfold
(C) Double
(D) Decrease

5 . If  these   compounds   were    separated   by  column  chromatography  with    ether   on  silica  gel,
which would elute first?

(A)  Benzyl alcohol
(B) Benzyl acetate
(C) p-Nitrophenol
(D) 1-Naphthalenemethanol

6 . Four    compounds,  I,  II, III,    and IV, are separated   by  chromatographic techniques.
Compound III is the most polar, II the least polar, and I and IV have intermediate polarity.
The solvent system is 85:15 ethanol:methylene chloride. Which spot on the card below
likely belongs to compound III?
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