Textbook Problem

The saturated calomel electrode. abbreviated SCE. is often used as a reference electrode in making electrochemica1 measurements. The SCE is composed of mercury in contact with a saturated solution of calomel (Hg₂Cl₂). The electrolyte solution is saturated KCI.  is +0.242 V relative to the standard hydrogen electrode. Calculate the potential for each of the following galvanic cells containing a saturated calomel electrode and the given half-cell components at standard conditions. In each case. indicate whether the SCE is the cathode or the anode. Standard reduction potentials are found in Table 17.1.

a. ${\text{Cu}}^{\text{2+}}+2{\text{e}}^{-}\to \text{Cu}$

b. ${\text{Fe}}^{3+}+{\text{e}}^{\text{-}}\to {\text{Fe}}^{2+}$

c. $\text{AgCl}\text{+}{\text{e}}^{\text{-}}\to \text{Ag}+{\text{Cl}}^{\text{-}}$

d. ${\text{Al}}^{3+}+3{\text{e}}^{-}\to \text{Al}$

e. ${\text{Ni}}^{2+}+2{\text{e}}^{-}\to \text{Ni}$