I have seen several examples:
- The fact that maleic acid is more soluble in water than fumaric acid in spite of the fact that it must be able to show intramolecular hydrogen bonding.
- trans-Cyclopentane-1,2-dicarboxylic acid is more stable than the cis form (cis form should be able to show hydrogen bonding).
- o-Nitrobenzoic acid is more acidic than the para isomer.
I tried linking point 1 to acidic strength (maleic acid > fumaric acid because of hydrogen bonding in conjugate base) and point 3 to acidic strength (o-nitrophenol < p-nitrophenol)
What am I missing? Something related to the size of the ring?