Chapter 21.3, Problem 25LC

Interpretation Introduction

Interpretation: Whether the redox reaction in a voltaic cell releases free energy or not needs to be determined. If no electrical energy is supplied to a redox reaction in an electrolytic cell release free energy or not needs to be explained.

Concept Introduction: In electrochemistry, the relationship between electrical potential differences and potential differences due to chemical change is explained. The two types of cells that can be studied in electrochemistry are electrolytic cells and voltaic cells.

Explanation of Solution

A voltaic cell is a type of electrochemical cell which is used to convert chemical energy into electrical energy. Here, spontaneous redox reaction within the cell produces electrical energy. Thus, the redox reaction in a voltaic cell releases free energy if it is spontaneous.

An electrolytic cell is used to convert electrical energy to chemical energy. Here, direct current is used to make a nonspontaneous reaction to proceed in the forward direction. Since the non-spontaneous reaction generally does not take place, thus, if electrical energy is not supplied, a redox reaction in an electrolytic cell does not release free energy.