Question

1. which of the following are not absorbent for TLC?

a. magnesium silicate
b. polyamides
c. silica gel-F ( fluorescing indicator added)
d. starch
e. alumina
f. none of the above

2. select the best answer from the statements below about thin layer chromatography
A. in normal phase thin layer chromatography the stationary phase is polar silica gel
b. in normal phase thin layer chromatography the mobile phase is an organic solvent or a mixture of organic solvents Which is less polar than the stationary phase
c. in reversed phase thin layer chromatography the stationary phase is a silica bonded with an organic substrate such as a long chain aliphatic acid-like C 18
d. in reversed phase thin layer chromatography the mobile phase is a mixture of water and organic solvent which is more polar than the stationary phase.
e. all of the above are true

3. which of these statements are true about the absorbent silica gel
a. silica gel is the most common absorbent used in TLC
b. may come with a fluorescing indicator added to it to make visualization or detection of sample spots easier
c. silica gel is polymer based on silica to oxygen linkages with many hydroxyl groups extending from this mixture
d. the separation characteristics of silica gel is related to their porosity and their large surface area
e. all of the above are true

Answer 1