CC(=O)C1(O)CC2(c3ccccc3)C(=O)C1(c1ccccc1)C(c1ccccc1)=C2c1ccccc1
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?