Cc1ccccc1-c1nc(C[S+]([O-])CC(=O)NCCc2ccc(Cl)cc2)c(C)o1
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?