Chapter 21, Problem 78A

(a)

Interpretation Introduction

Interpretation: In the given electrolyte cell, MX is an ionic compound. The electrode at which reduction occurs needs to be identified.

Concept Introduction: In electrolytic cells, an electric current makes a non-spontaneous redox reaction take place. The process by which electrical energy is converted to chemical energy is known as electrolysis.

Explanation of Solution

In an electrolytic cell, the anode is a positive electrode (as it is connected to the positive terminal of the battery) and the cathode is a negative electrode (connected to the negative terminal of the battery). Also, in an electrolytic cell, reduction occurs at the cathode. Thus, the negative electrode shown on the right-hand side is where reduction occurs.

(b)

Interpretation Introduction

Interpretation: The electrode at which electrons are being released by ions needs to be identified.

Concept Introduction: In electrolytic cells, an electric current makes a non-spontaneous redox reaction take place. The process by which electrical energy is converted to chemical energy is known as electrolysis.

Explanation of Solution

Electrons are released by ions when oxidation takes place. In an electrolytic cell, oxidation occurs at the anode. Also, in an electrolytic cell, the anode is a positive electrode (as it is connected to the positive terminal of the battery) and the cathode is a negative electrode (connected to the negative terminal of the battery). Thus, the positive electrode shown on the left-hand side is where oxidation occurs.

(c)

Interpretation Introduction

Interpretation: The electrode at which electrons enter the cell needs to be identified.

Concept Introduction: In electrolytic cells, an electric current makes a non-spontaneous redox reaction take place. The process by which electrical energy is converted to chemical energy is known as electrolysis.

Explanation of Solution

The movement of electrons takes place from the positive to the negative electrode of an electrolytic cell; thus, the electrode at which electrons enter the cell is the negative electrode.

(d)

Interpretation Introduction

Interpretation: The electrode at which elemental M is formed needs to be identified.

Concept Introduction: In electrolytic cells, an electric current makes a non-spontaneous redox reaction take place. The process by which electrical energy is converted to chemical energy is known as electrolysis.

Explanation of Solution

According to the question, given electrolyte MX is an ionic compound. The formation of elemental M from its ion takes place after reduction. Since reduction occurs at the cathode (negative electrode), thus, the electrode at which elemental M is formed is the right-hand side electrode.