4. Solving a chemistry problem

6. For redox element type: Pt | A, B || C, D | Pt using standard electrode potentials of half-cells, write an equation and calculate the equilibrium constant of the oxidation-reduction reaction. Calculate emf. element (T=298 K). Indicate whether it is possible to practically change the direction of the reaction by changing the concentration of the components Accept aH2O = 1 an = 0.2
N option A B C D aA aB aC aD
6 Fe3 Fe2 Cr3 Cr2 0.005 0.15 0.1 0.001