COc1ccc(Cl)cc1-c1n[nH]c(SCC(=O)NC2CCS(=O)(=O)C2)n1
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?