Question

Referring back to question 6 above, in the TLC plate on the left the mobile solvent phase was ethyl acetate, in the plate on the right it was 97% ethyl acetate and 3% methanol. Explain why the Rf values in the plate on the right are larger than those in the plate on the left. Your explanation must be in the terms of intermolecular forces, you are not allowed to only use the word "polarity".

Answer 1

Answer:

Polarity is a measure of molecule's electrical charge which means that molecule or it's groups can have a dipole moment and also make hydrogen bonds.

Explanation:

So in terms of polarity methanol is more polar then ethyl acetate due to it's higher dipole moment and that it is a stronger hydrogen bond acceptor and also can be a hydrogen bond donor. So if we add methanol to the elutioning system it becomes more polar because and our compound moves faster on tlc due to methanol providing some more hydrogen bonds to it and increasing dipole-dipole interactions.