In view of this convention, the half reaction for the Daniell cell in
Fig 2 1 can be written as:
Left electrode: Zn(s) ® Zn
2+ (aq, 1 M) + 2 e
–
Right electrode: Cu
2+ (aq, 1 M) + 2 e
– ® Cu(s)
The overall reaction of the cell is the sum of above two reactions
and we obtain the equation:
Zn(s) + Cu
2+ (aq) ® Zn
2+ (aq) + Cu(s)
emf of the cell = Eo
cell = Eo
R – Eo
L
= 0 34V – (– 0