Consider the figure and answer the following questions.

1.  Cell A’ has Ecell = 2V and Cell ‘B’ has Ecell = 1.1 V which of the two cells ‘A’ or ‘B’ will act as an electrolytic cell. Which electrode reactions will occur in this cell?

2.  If cell A’ has Ecell = 0.5V and cell ‘B’ has Ecell = 1.1 V then what will be the reactions at anode and cathode?

 

 
(i) Cell ‘B’ will act as electrolytic cell due to its lesser value of emf.
The electrode reactions will be
 
At cathode Zn2+ + 2e- Zn
At anode Cu Cu2+ + 2e-
 
(ii) If cell ‘B’ has higher emf, it acts as galvanic cell.
Now it will push electrons into cell ‘A’
 
In this case, the reactions will be
 
Zn Zn2+ + 2e-     (At anode)
Cu2+ + 2e- Cu   (At cathode)