O=C1C2C3C=CC(C3)C2C(=O)N1Nc1c(Cl)cc(Cl)cc1Cl
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 negative pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the negative pKa value of this molecule?