Cadmium standard reduction potentials

Although it is only slowly oxidized in moist air at ambient temperature, cadmium forms a fume of brown-colored cadmium oxide [1306-19-0] CdO, when heated in air. Other elements which react readily with cadmium metal upon heating include the halogens, phosphoms, selenium, sulfur, and tellurium. The standard reduction potential for the reaction... 

I". Cadmium sulfide (CdS) is used in some semiconductor applications. Calculate the value of the solubility product (Ksp) for CdS given the following standard reduction potentials ... 

Calculation of Cell emfs Using Standard Reduction Potentials Note that in the case of the cadmium-silver cell above the emf of the cell equals the standard electrode potential of the cathode minus the standard electrode potential of the anode. So, alternatively, you can calculate any cell emf using the equation... 

In contrast to the silver electrode, the cadmium electrode is negative with respect to the standard hydrogen electrode. Consequently, the standard electrode potential of the Cd/Cd " couple is by convention given a negative sign, and Ecd icd — —0.403 V. Because the cell potential is negative, the spontaneous cell reaction is not the reaction as written (that is, oxidation on the left and reduction on the right). Rather, the spontaneous reaction is in the opposite direction. 

Consider a voltaic ceU constructed from a cadmium electrode and a silver electrode having the following reduction half-reactions and corresponding standard electrode potentials (reduction potentials) ... 

Since the half-wave potential is characteristic of the particular reaction that is occurring at that potential, it is possible to identify the species involved. A simple case is shown in Figure 3 where a mixture of metal ions was analyzed. The two reduction waves for copper occur at -0.1 and -0.35 V, cadmium at -0.69, nickel at -1.10 and zinc at -1.35 V. This illustrates an analysis that may identify the species qualitatively and, by using a standard addition method, can also determine the ions quantitatively. 

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