O=C(NNC(=O)c1cc(F)c(F)cc1Cl)c1ccc(NS(=O)(=O)c2cccs2)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?