The Acid Dissociation Constant for a Weak Acid HX at 23°C

The acid dissociation constant for a weak acid HX at 23°C is 4.78 * 10^-8. Calculate the free energy of formation for X^-(aq) at 23°C. The standard free energies of HX(aq) and H⁺(aq) at 23°C are -252.2 kJ/mol and 0, respectively.

A) -294 kJ/mol
B) -234 kJ/mol
C) -211 kJ/mol
D) 211 kJ/mol
E) 294 kJ/mol