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After the first deprotonation of maleic acid, an intramolecular hydrogen bond can form in the hydrogen maleate ion (hc4h2o4-) but it cannot form in the case of fumaric acid deprotonation. draw the structures of both deprotonated isomers and explain how the difference in cis and trans arrangements allow the single-deprotonated form of maleic acid to form a hydrogen bond with itself but fumaric acid cannot form a similar hydrogen bond when it has lost just one of its two acidic protons.

Respuesta :

Fumaric and maleic acids are isomers and cis of each other. If COO∧-group which makes the bonding of hydrogen which is more likely since Hydrogen will be attracted by the negative group. Since COOH group are trans to each other, then fumaric acid has no chance of happening and it has no way to form a ring which is through bonding hydrogen. 
Stable species will be formed for example carboxylic acids are acids this is because COO∧-group is somewhat been stabilized through resonance. Now in maleic has the extra stabilization which is offered through intermolecular of bonding hydrogen then maleic acid should have a high ionization constant more than fumaric acid.
Alcohol does not behave as acids in water the presence of a double bond adjacent to the OH group it decreases the pKa be the mechanism of keto-enol tautomerism.

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