O=[N+]([O-])c1cc([N+](=O)[O-])c2[nH]nc(-c3ccccc3)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?