The Ka for HF is 7.2 x 10⁻⁴. What is ΔG at 25°C for a reaction mixture that is 1.5 x 10⁻³ M in F⁻, 4.5 x 10⁻² M in HF with a pH of 2.75? The answer should be in kJ.

A) -20.5 kJ
B) -15.2 kJ
C) -10.8 kJ
D) -8.2 kJ