O=C(CCS(=O)(=O)c1nc(-c2cccs2)cc(C(F)(F)F)n1)Nc1cc(Br)ccc1O
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?