Chapter 21.3, Problem 23LC

Interpretation Introduction

Interpretation: Whether oxidation or reduction takes place at the cathode of an electrolytic cell needs to be identified.

Concept Introduction: In an electrolytic cell, oxidation takes place at the anode and reduction takes place at the cathode. In oxidation, electrons are released and in reduction, electrons are added to the reactant. The oxidation state of the reactant increases during oxidation and decreases during reduction.

Explanation of Solution

In an electrolytic cell, a redox reaction takes place. In a redox reaction, oxidation and reduction of species take place simultaneously. Here, oxidation occurs by loss of electron/s and reduction occurs by the gain of electron/s. In oxidation, the oxidation state of the species increases, and in reduction, the oxidation state of the species decreases. There are two electrodes in an electrolyte cell that is anode and cathode. At the anode, oxidation takes place and at the cathode, reduction takes place.

Thus, reduction always occurs at the cathode of an electrolyte cell.