Consier the Fig. given below and answer the following questions:
(i) Cell 'A' has `E_(cell)=2V` and Cell 'B' has `E_(cell)=1.1`V. Which of the cell 'A' or 'B' will act as an electrolytic cell. Which electrode reactions will occur in this cell?
(ii) If cell 'A' has `E_(cell)=0.5V and ` cell 'B' has `E_(cell)=1.1`V then what will be the reactions at anode and cathode?

Explanation

(i) Cell 'B' will act as an electrolytic cell as it has lower emf. Reactions occurring in cell A will be
`ZntoZn^(2+)+2e^(-)` (at Zn electrode),
`Cu^(2+)+2e^(-)Cu` (at Cu electrode)
Zn plate will act as -ve pole and supply electrons to electrode 'A', i.e., reduction of ions present in cell B will occur on electrode 'A' and oxidation on electrode 'B'
As cell (B) has higher emf, cell B will act as a source of external emf and reactions occurring in cell A will be reversed, (electrons will now flow from cell B to cell A), i.e,
`Zn^(2+)toZn` (Reduction at cathode)
`CutoCu^(2+)+2e^(-)` (oxidation at anode).