Why do Maleic Acid and Fumeric Acid differ so much in physical properties? How can one explain it in term of intramolecular forces and intermolecular forces?

Question

anonymous · Answer

the chemical formula of maliec acid and fumaric acid is same but properties are different because these two acids are geometrical isomers of each other. maleic acid is the cis form and fumaric acid is the trans form. so maleic acid having the intramolecular hydrogen bonding and fumaric acid have inter molecular H- bonding. so their physical properties are different

anonymous · Answer

So, let me ask a question that is a spinoff of that... If I did a TLC analysis of both, why do fumeric acid have a greater Rf than maleic. Is it because Maleic tends to create more hydrogen bonding compare to Fumeric acid? Because fumeric acid is more "tight" together because of their intermolecular force?

anonymous · Answer

@MarcLeclair very good question.........
one point is the polarity of the two acids . usually in the technique of TLC we use silica gel which is polar in nature. now, the more polar one will "stick" to the gel and will have a hard time moving up the sheet. so in your case the maleic acid is more polar than the fumaric acid because it got stuck to the silica gel on the plate and had a hard time moving up. where as the fumaric acid is less polar so it didnt stick as much to the plate, and could move up the plate faster. so fumaric acid have a greater Rf than Maleic acid