Cn1c(CNC(=O)CSc2nc(-c3cccc(Cl)c3)nc3cc(=O)[nH]n23)nc2ccccc21
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?