Ethyl acetate is another common organic solvent used in the type of TLC experime

Question

Ethyl acetate is another common organic solvent used in the type of TLC experiment you performed: it has a higher molecular weight and boiling point than either petroleum ether or diethyl ether, and is more polar than them as well. If ethyl acetate had been used as the mobile phase for a TLC analysis of F and AF, how would their Rf values compare to those found using the 1:1 solvent mixture you used? That is, predict how the behavior of F would change and how the behavior of AF would change. Be as specific as possible and explain your reasoning briefly ("Rf of F would be lower, because F is too soluble in ethyl acetate", "Rf of AF would be greater because the solvent front of the more polar solvent moves further on the polar plate", etc.) or state briefly why this cannot be answered. AF=acetylferrocene f=ferrocene (1:1 diethyl ether / petroleum ether solution)

Explanation / Answer

F = Ferrocene

AF=acetylferrocene

F is more non-polar than AF.

The polarity of ethyl acetate is more than the solvent system of 1:1 diethyl ether / petroleum ether.

So, when you use ethyl acetate as the mobile phase for a TLC analysis of F and AF. Both (A and AF) will move further greater distance as were moved in 1:1 solvent system.

F will move till the solvent front (or just below). So, Rf value will decrease.

FA will also travel more distance as it moved in 1:1 solvent system. So, Rf value will decrease.

Now, "the more polar solvent moves further on the polar plate"
You calculate Rf as the ratio of distance travel by the compound to distance travel by the solvent. Hence the statement makes no sense.

In summary, when you use ethyl acetate as the only mobile phase, both F and FA will travel greater distance than it travelled in 1:1 solvent mixture.

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