The oxidation of ferrous iron (Fe2+) to ferric iron (Fe3+) by molecular oxygen can be described by the following reaction:4R"(aq) + 02(3) + «ii-Natl) - 4Fc"(aq) + 2H20(l)(a) Using free energies of formation, calculate the equilibrium constant for this reaction at 25°C.(b) For a water in equilibrium with the atmosphere, a pH of 20, and a total soluble iron concentration of 1 mg/ L, calculatethe concentrations of Fe2+(aq) and Fe3+{aq).