Cc1cc(O)nc(NN2C(Cl)C(=O)C2c2ccc([N+](=O)[O-])cc2)n1
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?