Cc1cccc(/N=N/c2c(C)nn(C(=O)CC(=O)Nc3ccc(Cl)cc3)c2C)c1
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?