Br.N=C1c2ccccc2CN1NC(=O)c1cccc(S(=O)(=O)N2CCCCC2)c1
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?