Comment
Author: Admin | 2025-04-28
Standard Cell PotentialsWhat is the standard potential of the galvanic cell shown in Figure 17.2.2?Show SolutionThe cell in Figure 17.2.2 is galvanic, the spontaneous cell reaction involving oxidation of its copper anode and reduction of silver(I) ions at its silver cathode:[latex]\begin{array}{rl}{}\ce{cell reaction:}& \ce{Cu}(s) + \ce{2Ag+} (aq) \longrightarrow \ce{Cu^2+} (aq) + \ce{2Ag} (s)\\ \text{anode half-reaction:}& \ce{Cu}(s) \longrightarrow \ce{Cu^2+} (aq) + \ce{2e-}\\\text{cathode half-reaction:}& \ce{2Ag+} (aq) + \ce{2e-} \longrightarrow \ce{2Ag} (s)\end{array}[/latex]The standard cell potential computed as[latex]\begin{array}{rl}{}\text{E}^{\circ}_{\text{cell}} &=& \text{E}^{\circ}_{\text{cathode}} - \text{E}^{\circ}_{\text{anode}}\\ &=& \text{E}^{\circ}_{\ce{Ag}} - \text{E}^{\circ}_{\ce{Cu}}\\ &=& 0.7996 \text{V} - 0.34 \text{V}\\ &=&+0.46 \text{V}\end{array}[/latex]Check Your LearningIntrepreting Electrode and Cell PotentialsThinking carefully about the definitions of cell and electrode potentials and the observations of spontaneous redox change presented thus far, a significant relation is noted. The previous section described the spontaneous oxidation of copper by aqueous silver(I) ions, but no observed reaction with aqueous lead(II) ions. Results of the calculations in Example 1 have just shown the spontaneous process is described by a positive cell potential while the nonspontaneous process exhibits a negative cell potential. And so, with regard to the relative effectiveness (“strength”) with which aqueous [latex]\ce{Ag+}[/latex] and [latex]\ce{Pb^2+}[/latex] ions oxidize [latex]\ce{Cu}[/latex] under standard conditions, the stronger oxidant is the one exhibiting the greater standard electrode potential, E°. Since by convention electrode potentials are for reduction processes, an increased value of E° corresponds to an increased driving force behind the reduction of the species (hence increased effectiveness of its action as an oxidizing agent on some other species). Negative values for electrode potentials are simply
Add Comment