| Date | May 2014 | Marks available | 2 | Reference code | 14M.3.sl.TZ2.2 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Calculate and Outline | Question number | 2 | Adapted from | N/A |
Question
Thin-layer chromatography (TLC) is an example of adsorption chromatography.
A mixture of two organic compounds was separated by TLC using a non-polar solvent.
(i) Calculate the \({R_{\text{f}}}\) values of A and B.
(ii) Outline why compound B has travelled the greater distance.
Markscheme
(i) 
;
Award [1] for both correct.
(ii) B is more soluble in solvent/mobile phase / B is less polar than A / B is less strongly adsorbed onto stationary phase;
Accept B is non-polar.
Do not allow “greater attraction/affinity to solvent” without reference to solubility.
Examiners report
(i) Very well answered. Many candidates used an inappropriate number of significant figures for the calculated \({R_{\text{f}}}\) values, but this was not penalized in this instance.
(ii) Generally well answered. Some candidates successfully related the solubility of compound B to its polarity.
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