C=CC[n+]1c(-c2ccc(Cl)cc2Cl)csc1Nc1c(C)n(C)n(-c2ccccc2)c1=O.[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?