O=C(Cc1ccccc1)NN1C(=O)C2C(C1=O)C1C=CC2C12CC2
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?