N/N=C(\C(=O)Nc1ccc([N+](=O)[O-])cc1)C(C1=Nc2cc([N+](=O)[O-])ccc2NC1)[N+](=O)[O-]
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?