N#CCC(=O)N/N=C(\C(=O)Nc1ccc(Cl)c(Cl)c1)C1CN(c2ccccc2)N=C1N
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?