CC(C)C1=C(Cc2ccccc2)C(=O)O/C1=C\c1ccc(O)c(Cl)c1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?