N#CC(/C(=N/NC(N)=S)C(=O)Nc1cccc(Cl)c1)c1ccccc1
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?