CC(=O)/C(=C\n1c(=S)[nH]c2ccc([N+](=O)[O-])cc21)C(=O)Nc1ccccc1C
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?