O=C(C[n+]1ccccc1)NNC(=O)/C(=C/c1ccc2c(c1)OCO2)NC(=O)c1ccccc1.[Cl-]
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?