Electrode Electrolyte Determination Given A Redox Reaction
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Electrode Electrolyte Determination Given A Redox Reaction

Figure 15.7 is a conceptual sketch of the construction of a galvanic cell based on the following spontaneous reaction:

3Fe(s) + 2Au3+ --------> 3Fe2+ + 2Au(s)

(a) Determine electrodes A and B, and electrolytes A and B in figure 15.7.
(b) What is the sign of the change in enthalpy for this reaction?

The strings:

S7P5A52 (Change - Chemical Change)

The math:
Pj Problem of Interest is of type change (chemical change). This problem is also an identity problem because we are determining the identities of the electrodes and electrolytes from the given redox reaction. However, the Pj Problem of Interest is cast as of type change because of the underlying chemical reaction in which the electrodes and electrolytes are participants.

The half-reactions of the cell are as follows:

Half-reaction at the anode:

Fe(s) -------> Fe2+ + 2e- oxidation reaction.

Half-reaction at the cathode:

Au3+ + 3e- -------> Au(s) reduction reaction

So, Electrode A (the anode) is an iron electrode and electrolyte A is a solution containing Fe2+ ions (e.g FeSO4)

So, Electrode B (the cathode) is a gold electrode and electrolyte B is a solution containing A3+ ions (e.g. AuCl3)

The reaction is spontaneous, the enthalpy change ΔH is negative.

Blessed are they that have not seen, and yet have believed. John 20:29