O=S(=O)([O-])c1cc(/N=N/c2c(O)ccc3ccccc23)c2c(S(=O)(=O)O)cccc2c1.[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?