O=C(CSc1oc(-c2ccco2)nc1S(=O)(=O)c1ccc(Cl)cc1)c1ccc(Cl)cc1
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?