COC(=O)c1cc(NC(=O)CN(c2ccccc2OC)S(=O)(=O)c2ccccc2)ccc1Cl
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?