23.2. Cell Potentials http://www.ck12.org
FIGURE 23.5
The standard hydrogen electrode is an
arbitrary reference cell that is assigned a
standard reduction potential of 0.00 V.FIGURE 23.6
(A) The standard hydrogen half-cell is
paired with a Cu/Cu^2 +half-cell. H 2 is
oxidized, while Cu^2 +is reduced. (B) The
standard hydrogen half-cell is paired with
a Zn/Zn^2 +half-cell. Zn is oxidized, while
H+is reduced.Oxidation: H 2 (g)→2H+(aq)+2e−
Reduction: Cu^2 ++2e−→Cu(s)
Overall: H 2 (g)+Cu^2 +(aq)→2H+(aq)+Cu(s)In this particular voltaic cell, the SHE is the anode (where oxidation takes place), while the copper half-cell is the
cathode. Electrons flow from the SHE to the copper electrode. The standard cell potential (E^0 cell) is the measured
value of 0.34 V, while the potential of the SHE is defined to be zero. This allows us to determine the reduction
potential of the copper half-cell.