COc1ccc(-c2sc(Nc3ccccc3)n[n+]2-c2ccc(F)cc2)c(OC)c1OC.[Cl-]
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?