Cc1c(O)c([S+]([O-])c2ccccc2)c(=O)n(-c2ccccc2)c1-c1ccccc1
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?