CHEMISTRY · Single correct · A Level · Chemistry · Electrode potentials · Electrode potentials
Problem
During operation of an electrochemical cell, the zinc electrode loses mass while bubbles of gas form at the copper electrode. Cations migrate toward the copper half-cell through the salt bridge. Which type of cell is most consistent with these observations and why?
(a) Electrolytic, because the appearance of gas at the copper electrode shows that energy is being consumed to drive a non-spontaneous decomposition.
(b) Galvanic, because cations should migrate toward the anode to replace the Zn2+ ions that are produced.
(c) Galvanic, because oxidation at zinc releases Zn2+ into solution and the spontaneous reaction produces gas at the cathode.
(d) Galvanic, because the copper electrode is negative as accumulated electrons attract cations through the salt bridge.