O=C(Nc1ccccc1)c1ccc2c(O)c(S(=O)(=O)c3ccc(Cl)cc3)c(=O)[nH]c2c1
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?