COC(=O)C(=C/c1ccc(OC)cc1)/C(C(=O)O)=C(/C)c1ccccc1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?