Reduction reactions, or more commonly known as Redox which is short for ‘reduction-oxidation’, are all chemical reactions in which atoms have their oxidation number, or oxidation state altered. An example can be a simple reduction reaction involving the oxidation of carbon which produces carbon dioxide, as well as a reduction of carbon using hydrogen to produce methane gas. A more complex and involved process would be the oxidation of the sugar in the human body which involves the transfer of electrons. Reduction reactions, or redox (reduction and oxidation), can be described in its simplest term such as; oxidation defines the loss of electrons or an increased oxidation state from a molecule, atom or an ion. Reduction defines the addition of electrons or a decreased oxidation state by a molecule, atom or ion.

While the above mentioned explanation is adequate, it is not exactly right. A better definition of oxidation and reduction is the actual change in oxidation numbers. A confirmed transfer of electrons may never take place. So perhaps more accurate explanation of reduction reactions would be stated as; the actual increase in oxidation numbers, or the actual decrease or reduction in oxidation numbers. While in some cases, a transfer of electrons will certainly cause a change in oxidation numbers, there are several reactions that are in the class of a reduction reaction, even though it is known that no electron transfers take place.

Oxidizing agents are described as substances that have the ability to oxidize other substances, are referred to as oxidative, and area also known as oxidants or oxidizers. These oxidants take away electrons from other substances, and in turn, reduce themselves. It is also called an electron acceptor because it is able to accept electrons. Typically, oxidants are chemical compounds that have a very high oxidation number. They can also be described as substances that are able to get one or two electrons by oxidizing another substance.

Compounds or substances that are able to reduce another substance are typically known as reducing agents or reducers and reductants. In simpler terms, a reductant has the ability to transfer electrons to another substance, in turn oxidize itself. These are also known as electron donors because they actually donate electrons to another substance. The reductants known to produce reduction reactions are a very assorted group in the chemistry world. Metal reduction reactions, or electropositive metals are known to be used. The key factor in these metals is that they have the ability to readily give away electrons. Another well known agent to cause reduction reactions are called hydride transfer reagents which are commonly used in organic chemistry.

One primary use of reductants to produce reduction reactions is used in the smelting of ore, reducing the ore into metal. Reduction reactions are widely used in a lot of industries to produce such common products as; cleaning products, a very common practice of oxidizing ammonia to make nitric acid, which is common in most fertilizers. Another very common place where reduction reactions are used is in the making of compact discs. The reduction process coats the disc in a very thin layer of metal.