O=C(CN1C(=O)COc2ccc(S(=O)(=O)NC3CCCC3)cc21)Nc1ccc(F)c(Cl)c1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?