Consider the cell,|| S.C.E cell solution |whose voltage is - 0.126 V. The cell solution contains 2.00 mmol of Fe(NH₄)₂(SO₄)₂, 1.00 mmol of FeCl₃, 4.00 mmol of Na₂EDTA, and lots of buffer, pH 6.78, in a volume of 1.00 L.

(a) Write a reaction for the right half-cell.

(b) Find the quotient [Fe²⁺]/[Fe³⁺] in the cell solution. (This expression gives the ratio of uncomplexed ions.)

(c) Find the quotient of formation constants: (Kf for FeEDTA^-)/ (Kf for FeEDTA^2-).