COc1ccc(N(CC(=O)Nc2cc(Cl)ccc2OC)S(=O)(=O)c2c(C)nc(O)nc2O)cc1
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?