1. Both maleic and fumaric acids can sequentially lose two protons from their carboxylic acid
groups. The reaction leading to loss of the first proton has a dissociation constant referred to as
pKai and the reaction from this anion leading to the loss of the second proton (to give a dianion)
has a dissocation constant referred to as pK2. Show these reactions.
The values of these dissociation constants are shown in the Table above. Clearly the values for
maleic acid are quite different from those for fumaric acid. In essence what these values show is
that maleic acid is unusual. Apparently it loses the first proton with unusual ease, and loses the
second one with unusual difficulty. From the structures involves, suggest why this might be so.