Explain the concepts of reduction and oxidation... - SS2 Chemistry Organic Chemistry III: Aldehydes, Ketones, and Carboxylic Acids Question

Reduction and oxidation, collectively known as redox reactions, are fundamental concepts in chemistry that involve the transfer of electrons between species. These processes are interconnected and occur simultaneously in a chemical reaction.

1.    Reduction: Reduction refers to the gain of electrons by a species, resulting in a decrease in its oxidation state. In a redox reaction, the species being reduced is called the oxidising agent, as it causes the reduction of another species. Reduction is characterised by an increase in the number of bonds to hydrogen or a decrease in the number of bonds to oxygen. For example:

2H+ + 2e- → H2

In this reaction, hydrogen ions (H+) are reduced by gaining two electrons to form hydrogen gas (H2).

2.    Oxidation: Oxidation refers to the loss of electrons by a species, resulting in an increase in its oxidation state. The species being oxidised is called the reducing agent, as it causes the oxidation of another species. Oxidation is characterised by a decrease in the number of bonds to hydrogen or an increase in the number of bonds to oxygen. For example:

Mg → Mg2+ + 2e-

In this reaction, magnesium (Mg) loses two electrons, resulting in the formation of magnesium ions (Mg2+).

Electrons play a crucial role in redox reactions as they are transferred from the reducing agent to the oxidising agent. The reducing agent is oxidised because it loses electrons, while the oxidising agent is reduced because it gains electrons. The oxidation state of an element or compound is a formal measure of the distribution of electrons in a molecule or ion.