O=C(CC(=O)N1N=C(c2ccccc2)C(/N=N/c2ccc(Cl)cc2)C1=O)Nc1ccccc1Cl
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?