Question

The Rf value of compound A is .34 when the TLC plate is developed in hexane and .44 when the plate is developed in diethyl ether. Compound B has an Rf value of .42 in hexane and .60 in diethyl ether. Which solvent would be better for seperating a mixture of compounds A and B by TLC? Explain.

- I think that the diethyl ether is a better solvent because it is less polar than hexane? Is this the right track?

Answer 1

I think either solvent will separate the two compounds; however, the diethyl ether separation will be farther apart and I would pick that one. As for hexane being more polar than diethyl ether, I don't think so. Hexane is about as non-polar as you can get while diethyl ether, while not very polar, is more polar than hexane. Here is a site that gives some general rules about polarity of various groups.
http://www.elmhurst.edu/~chm/vchembook/213boilingpoint.html

Answer 2

Thanks alot. yeah I was a little confused as to which was more polar.