Consider the corrosion of copper at 30°C using the overall reaction:

Cu(s) + 0.5 O2(g) + 2 H3O+(aq) → Cu2+(aq) + 3 H2O(l)

If the partial pressure of oxygen is 0.88 bar, and the concentration of Cu2+(aq) is 5.1 M, at what pH does the reaction become spontaneous?