question_answer 21)

In the button cells widely used in watches and other devices the following reaction takes place: Zn(s) + Ag2O(s) + H2O(l)  Zn2+(aq) + 2Ag(s) + 2OH? (aq). Determine and E° for the reaction. Given E0Ag+/Ag = 0.344V and E0Zn2+/Zn = ?0.76V

Answer:

In the cell, zinc is oxidised while silver is reduced. E0cell = E0cathode ? E0anode = (0.344) - (- 0.76) =1.10V The reactions occurring in the cell are (At cathode) = ?212300 CV = ?212300J.