Nc1ncnc2c1nc(Br)n2[C@@H]1O[C@H]2COP(=O)([O-])O[C@@H]2[C@H]1O.[Na+]
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?