O=C(Nc1c2c(nn1-c1ccc(Cl)cc1)CS(=O)(=O)C2)c1cccc(F)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?