Question

Which of the following statements regarding thin layer chromatography are TRUE? In thin layer chromatography, a polar organic compound will be repelled by the adsorbent and therefore travel not as far up the plate than a non-polar compound In thin layer chromatography, a polar organic compound will be attracted by the adsorbent and therefore travel not as far up the plate as a non-polar compound Sample spots should be approximately 1 cm in diameter. Covering the sample jar is done to prevent fingerprints on the slide. The Rf value will change if the adsorbent material is changed. Thin layer chromatography is an example of adsorption chromatography, and not partition chromatography.

Answer 1

Answer:

a) False

b) True

c) False

d) False

e) True

f) True

Explanation:

a) In thin layer chromatography, a polar organic compound will be repelled by the adsorbent and therefore travel not as far up the plate than a non-polar compound. FALSE. The adsorbent usually is a polar compound that will attract the polar organic compound.

b) In thin layer chromatography, a polar organic compound will be attracted by the adsorbent and therefore travel not as far up the plate as a non-polar compound. TRUE. The polar organic compound will be attracted by the adsorbent doing its travel not as far.

c) Sample spots should be approximately 1 cm in diameter. FALSE. Sample spots must be of 1-2 mm of diameter.

d) Covering the sample jar is done to prevent fingerprints on the slide. FALSE. The covering is doing to saturate the jar's air with solvent.

e) The Rf value will change if the adsorbent material is changed. TRUE. The travel of the compound depends of the retention that is made by the adsorbent material.

f) Thin layer chromatography is an example of adsorption chromatography, and not partition chromatography. TRUE. The mechanism of separation in thin-layer chromatography is differences of adsorption from different compounds.