80. Solving a chemistry problem

4.For redox cell type:
Pt | A, B || C, D | Pt
according to the standard electrode potentials of half-elements (Brief reference book of physical and chemical quantities. Edited by K.P. Mishchenko, A.A. Ravdel. 1974) 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

Variant No. A B C D aA aB aC aD
4* МnO4- Мn2 Sn4 Sn2 0.02 0.01 0.08 0.15