O=C1c2cccc3cc([N+](=O)[O-])cc(c23)C(=O)N1/N=C/c1ccc(O)cc1O
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?