O=C(COC(=O)Cn1cnc2ccccc21)Nc1cc2c(cc1Cl)C(=O)c1ccccc1C2=O
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?