Cc1ccccc1C(=O)Nc1ccc[n+](-c2nc3ccccc3nc2[N-]S(=O)(=O)c2ccccc2)c1
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?