CCC(C)Cn1c([O-])cc2nn(-c3nc4ccccc4s3)c(=O)c-2c1C.[Na+]
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?