If I have separate solutions of the compounds benzoic acid and benzaldehyde, and they are spotted on an alumina gel TLC plate and run using CH2Cl2 as the eluant, which compound will have the higher Rf value? Explain.

Answer 1

I would expect benzoic acid to be more polar than benzaldehyde. And I would expect dichloromethane, a polar eluent, to move the benzoic acid faster than benzaldehyde. So the higher Rf value would be ???? but get a second opinion.