O=C(NC(=S)Nc1ccc2[nH]c(O)nc2c1)c1cc(Br)ccc1Cl
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?