O=S(=O)([O-])c1cc(OS(=O)(=O)c2ccccc2)cc2ccccc12.[Na+]
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?