O=C(Cn1c(=O)oc2cc(S(=O)(=O)N3CCCCC3)ccc21)NCc1ccc(Cl)cc1
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?