Biomedical Engineering Reference
In-Depth Information
FIGURE 10.5
Distribution of charges at a metal/electrolyte interface.
TABLE 10.2
Half-Cell Potentials of Important Metals
Primary metal and chemical reaction
Half-cell potential (V)
Al
3þ
þ
3e
Al
!
1.706
Cr
3þ
þ
3e
Cr
!
0.744
Cd
2þ
þ
2e
Cd
!
0.401
Zn
2þ
þ
2e
Zn
!
0.763
Fe
2þ
þ
2e
Fe
!
0.409
Ni
2þ
þ
2e
Ni
!
0.230
Pb
!
Pb
2þ
þ
2e
0.126
2H
þ
þ
2e
H
2
!
0.000 (standard by definition)
Ag
þ
þ
e
Ag
!
þ
0.799
Au
3þ
þ
3e
Au
!
þ
1.420
Cu
2þ
þ
2e
Cu
!
þ
0.340
Cl
!
2e
Ag
þ
AgCl
þ
þ
0.223
EXAMPLE PROBLEM 10.2
Silver and zinc electrodes are immersed in an electrolyte solution. Calculate the potential drop
between these two electrodes.
Solution
From Table 10.2, the half-cell potentials for the silver and zinc electrodes are 0.799 V and
0.763 V, respectively. Therefore, the potential drop between these two metal electrodes is equal to
0
:
799V
ð
0
:
763V
Þ¼
1
:
562V