COc1c(O)cc2c(c1O)C1OC(CO)C(O)C(O)C1OC2=O.O
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?