O=C(Nc1ccc(S(=O)(=O)Nc2cnc3ccccc3n2)cc1)c1cc(F)c(F)cc1Cl
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?