Chapter 21, Problem 56A

Interpretation Introduction

Interpretation: The meaning for the standard reduction potential for a cadmium half-cell value -0.40 V needs to be explained.

Concept Introduction: In a voltaic cell, oxidation takes place at anode and reduction takes place at 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 it decreases during reduction.

Explanation of Solution

The standard reduction potential for cadmium half-cell is given -0.40 V. The value is negative thus, oxidation of cadmium to cadmium ion takes place more simultaneously that is oxidation of cadmium. Thus, the cadmium half-reaction is represented as follows:

  $\text{Cd}\left(s\right)\to {\text{Cd}}^{2+}+2e\left(aq\right)$