COc1cc(-c2[o+]c3cc(O)cc(OC4OC(CO)C(O)C(O)C4O)c3cc2OC2OC(CO)C(O)C(O)C2O)cc(OC)c1O.[Cl-]
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?