40. Solving a chemistry problem

7. For a redox element of the type Pt | A, B | | C, D | Pt according to the standard electrode potentials of half-cells (Handbook of physico-chemical quantities), write an equation and calculate the equilibrium constants of the oxidation-reduction reaction. Calculate the EMF of the element at 298 K. Consider that αH2O=1, αH2=0.2
Variant No. A B C D aA aB aC aD
7 Fe(CN)63- Fe(CN)64- Co3 Co2 0.06 0.06 0.04 0.005