Question

Part I:
1. Look at the chemical structures of aspirin and acetaminophen. What functional group is found on aspirin and not on acetaminophen?

Part II:
1. Thin Layer Chromatography was performed on an unknown compound. The compound traveled 32.5mm while the solvent front measured to be 50.1mm from the origin (i.e., the initial spotting). Calculate the Rf value.

2. Define the following terms:
   a) Thin Layer Chromatography
   b) Solvent front
   c) Developing/TLC chamber
d) Analgesic
e) Caffeine

Answer 1

1 )

carboxylic acid functional group , ester functional groups are present in aspirin but these are absent

2 )

Rf = compound traveld / solvent traveld

Rf = 32.5 / 50.1

Rf = 0.65

2)

a)

chromatography in which compounds are separated on a thin layer of adsorbent material, typically a coating of silica gel on a glass plate or plastic sheet.

b) In chromatography, the retardation factor (R) is the fraction of an analyte in the mobile phase of a chromatographic system. In planar chromatography in particular, the retardation factor R_f is defined as the ratio of the distance traveled by the center of a spot to the distance traveled by the solvent front.

c)

d) Analgesic it is a drug used for the relieve pain.

example :Aspirin , depressents

e) caffine :

an alkaloid compound which is found especially in tea and coffee plants and is a stimulant of the central nervous system