C=C1[C@@H](OC(C)=O)/C=C/C2C3C(=O)[C@@](C)(OC(C)=O)[C@H]([C@H](OC(C)=O)[C@]4(O)[C@@H](C)C(=O)O[C@H]4[C@H]1Cl)[C@@]23C
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?