Chapter 21, Problem 21.84P

Interpretation Introduction

Interpretation:

The reason behind the given statement that why ${\text{E}}_{\text{half-cell}}$ values water oxidation and reduction is different from ${\text{E}}^{\text{o}}{}_{\text{half-cell}}$ values for same process has to be stated.

Concept Introduction:

Oxidation: The gain of oxygen or the loss of hydrogen or the loss of an electron in a species during a redox reaction is called as oxidation.

Reduction: The loss of oxygen or the gain of hydrogen or the gain of an electron in a species during a redox reaction is called as reduction.

Oxidizing agent: The substance that is oxidized is called as a reducing agent.

Reducing agent: The substance that is reduced is called as an oxidizing agent.

Oxidation half-reaction: An oxidation half-reaction is a part of redox reaction that shows only for the oxidized species with electrons and its oxidation state increases with the loss of electrons.

Reduction half-reaction: A reduction half-reaction is a part of redox reaction (counterpart of oxidation half-reaction) that shows only for the reduced species with electrons and its oxidation state decreases with the gain of electrons.

Anode: The electrode where the oxidation occurs is called as an anode. It is a negatively charged electrode.

Cathode: The electrode where reduction occurs is called as a cathode. It is a positively charged electrode.

${\text{E}}_{\text{cell}}$-the potential difference between anode and cathode in cell is determined as cell potential.

${\text{E}}^{\text{o}}{}_{\text{cell}}$-the cell potential measured at specified temperature conditions which is used to compare the potentials of different cells since, the ${\text{E}}_{\text{cell}}$ is affected by concentration changes as reaction proceeds and due to energy loss from heating of the cell and external circuit.