CHEMISTRY · Multi-part · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry
Problem
An engineer has access to identical beakers, electrodes, and 1.0 M Fe³⁺/Fe²⁺ solutions and wishes first to construct a galvanic cell and later to operate the same hardware as an electrolytic cell that produces solid iron on one electrode.
A porous frit is available to permit ion migration without bulk mixing of the two half-cell solutions.
(a) For the galvanic configuration, propose a complete cell diagram using standard electrochemical notation. Clearly indicate the phase boundary symbols and the direction of electron flow.
(b) Describe the purpose of the porous frit in the galvanic cell and predict the direction of ion migration through it during operation.
(c) The engineer now connects an external power supply so that solid iron is deposited from Fe²⁺(aq). Identify which electrode becomes the cathode under electrolytic conditions and explain your reasoning in terms of the half-reaction occurring there.
(d) Compare how the sign conventions for anode and cathode, as well as the direction of cation migration, differ between the galvanic and electrolytic modes for this apparatus.
(e) Discuss two practical challenges that must be addressed when converting the galvanic setup into an efficient electrolytic cell capable of high-purity iron deposition.