Zn(s) + Cu2+(aq) ® Zn2+ (aq) + Cu(s)
This reaction is a combination of two half reactions whose addition
gives the overall cell reaction:
(i) Cu2+   +  2e–    ® Cu(s)
(reduction half reaction)
(2 2)
(ii) Zn(s)  ® Zn2+ + 2e–
(oxidation half reaction)
(2 3)
These reactions occur in two different portions of the Daniell cell The reduction half reaction occurs on the copper electrode while the
oxidation half reaction occurs on the zinc electrode