O=C1CN(C(=O)c2ccc(Br)o2)C(c2ccc(F)cc2)c2cc(Cl)ccc2N1
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?