23.2. Cell Potential http://www.ck12.org
- Which species in the following pairs is more likely to be reduced? Explain your answer.
(a) Br 2 or Cl 2
(b) Na+or K+
(c) PbO 2 or PbSO 4 - Using the given table of standard reduction potentials, calculate E° for the following reactions. Under standard
conditions, will these reactions spontaneously occur in the forward direction?
(a) Al + 3Ag+→3Ag + Al^3 +
(b) Zr + 2I 2 →Zr^4 ++ 4I−
(c) Li++ Ag→Ag++ Li - Define each quantity that appears in the Nernst equation, and make note of the respective units.
- Use the Nernst equation and the given concentrations to calculate E for the following reaction at 25°C:
NO 3 −(aq) + As(s)→NO(aq) + AsO 2 −(aq), where [NO 3 −] = 1.0 M, [NO] = 0.20 M, and [AsO 2 −] = 0.010
M. E° for this reaction is equal to +2.91 V. - Use the Nernst equation and the given concentrations to calculate E for the following reaction at 25°C: 2H 2 O(l)
- 3Cl 2 (g) + 2Sb(s)→6Cl−(aq) + 2SbO+(aq) + 4H+(aq), where [Cl 2 ] = 0.80 M, [Cl−] = 1.0 M, [SbO+] =
0.20 M, and [H+] = 0.20 M. E° for this reaction is equal to +2.34 V.
- 3Cl 2 (g) + 2Sb(s)→6Cl−(aq) + 2SbO+(aq) + 4H+(aq), where [Cl 2 ] = 0.80 M, [Cl−] = 1.0 M, [SbO+] =
Further Reading/Supplementary Links
- Table of standard reduction potentials: http://www.jesuitnola.org/upload/clark/refs/red_pot.htm
- Derivation of the Nernst equation: http://www.science.uwaterloo.ca/~cchieh/cact/c123/nernsteq.html
- Using the Nernst equation: http://www.asdlib.org/onlineArticles/ecourseware/Gross_Potentiometry/The%20N
ernst%20Equation.pdf
Points to Consider
- How would comparing elements in the activity series by their standard reduction potentials allow us to make
predictions about the direction of oxidation-reduction reactions?