O=C(O)C(Cc1cc2ccccc2[nH]1)N1C(=O)C2CC=C(Cl)CC2C1=O
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?