Answer:
E) 0.90
Explanation:
In TLC (Thin-Layer-Chromatography) retention factor RF is defined as the ratio between distance of the sample and the solvent front. RF is very important in chemistry to know the composition of any sample by comparison.
In the problem, as the sample has a distance of 0,20cm from the solvent front, the distance of the sample is:
2,0cm - 0,20 cm =<em> 1,8 cm</em>. Thus, RF is:
RF = 1,8cm / 2,0cm = 0,90
<em>E) 0,90</em>
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I hope it helps!