O=C1NC(Cc2ccccc2)c2nc3ccc(Cl)cc3c(=O)n2-c2ccc(Cl)cc21
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?