Understanding the relationship between reduction and oxidation, commonly known as 'redox' reactions, is key to grasping many chemical processes, including those in biochemistry and environmental chemistry.
In simple terms, oxidation is the process where an atom, ion, or molecule loses one or more electrons. Conversely, reduction is the gain of one or more electrons. These two processes always occur together; when one substance is oxidized, another is reduced. This pair of simultaneous reactions is what we refer to as a redox reaction.
For example, in the reaction where iron rusts:
- Iron (Fe) is oxidized as it loses electrons to form iron oxide (Fe_2O_3).
- Oxygen, in this case, is reduced as it gains electrons from iron.
Considering the education exercise at hand, when a substance is reduced, it 'gains' electrons, which can be counterintuitive since the term 'reduction' might imply a decrease, but it's actually referring to a decrease in oxidation state - an increase in electrons.