Oxidising agent

An oxidising agent is a chemical substance that causes another chemical substance to species chemical species loses electrons. Oxidation means the loss of electrons, the loss of an atom of hydrogen or the addition of a oxygen. The oxidising agent has the ability to accept or transfer these electrons.

General description of the oxidising agent

An oxidising agent can be compared to a reducing agent or a chemical that makes another molecule gains electrons. The agent capable of oxidising another species causes it to lose electrons. Alternatively, the oxidising agent can be the addition of oxygen to a chemical species. The oxygen pulls electrons away from other parts of the molecule, effectively oxidising the entire molecule. In other cases, as we shall see in the examples, the oxidising agent is separate from the reducing agent but allows the transfer of electrons to complete the Reduction-Oxidation reactionor Redox reaction for short.

Redox reactions always consist of two half-reactionswhether they occur together or not. The reduction reaction occurs when a chemical species gains electrons. These electrons must come from somewhere and are lost from another chemical species in a previous process. This process is known as oxidation. The oxidant, or oxidising agent, is responsible for removing these electrons. The agent may be directly involved in the reaction, or it may be a catalyst that simply drives the removal of electrons from a substance.

List of oxidising agents

An oxidising agent can be any chemical species that is prone to accept electrons. Thus, things like acids are often oxidising agents because of their propensity to absorb more electrons. Several common oxidising agents are shown below:

• Oxygen
• Fluorine
• Chlorine
• Nitric acid
• Hydrogen peroxide
• AND MANY MORE…

Examples of oxidising agents

Forming salt in the laboratory

Table salt is an extremely simple combination of two elements: sodium and chlorine. While most commercially produced salt is obtained by extracting prefabricated salt from nature, it can be produced in the laboratory. By combining solid metallic sodium in a chlorine gas atmosphere, the sodium will be oxidised. This oxidation reaction is accompanied by a chlorine reduction reaction. In other words, sodium loses an electron and becomes the sodium cation (positive ion). Chlorine gains the electron, becoming a negative anion. Together, these two ions form the ionic compound sodium chloride or table salt. Interestingly, while table salt is mostly harmless, chlorine gas is an extremely toxic compound.

Part of the reason chlorine gas is so lethal is that it is an extremely powerful oxidising agent. Chlorine is very reactive and usually tries to extract electrons. While oxidation can turn metal into salt, it can also react dangerously with the body’s many chemical reactions, siphoning off much-needed electrons and causing chaos. Fortunately, oxidising agents only work in one direction. You don’t have to worry about poisoning yourself with your table salt.

The fruit battery

Another interesting oxidising agent is presented in the form of a classical classroom demonstration. The fruit battery, also known as the lemon or potato battery, is a form of electric current produced by the effects of redox reactions. Two probes are placed on either side of a lemon or other fruit or vegetable. One probe, made of zincis connected through a lamp to the other probe made from copper.

The zinc probe, in the presence of the acidity of the fruit, begins to dissolve in the fruit. It does this by being oxidised by the acids in the fruit. The acid acts as a catalyst, allowing some of the zinc atoms to break their bonds with the other zinc by leaving behind the electrons that hold them in the matrix. The electrons, which are now accumulating in the zinc probe, try to distribute themselves evenly along the probe. Meanwhile, in the copper probe, the copper acts as a catalyst to reduce the hydrogen ions into hydrogen gas. The copper deposits excess electrons on the hydrogen ions, which can then form covalent bonds with each other. This creates small bubbles around the copper probe.

Thus, on one side of the fruit battery, there is a demand for electrons and on the other side, there is an excess of electrons. The copper wire connecting the two probes through a light acts as a conductor, allowing an easy path for the electrons to flow. As the electrons flow from the zinc to the copper, they can release some of their energy into the bulb and create light. The concepts described above can be seen in the image below, which is a diagram of any simple battery. The fruit battery, although some erroneously claim that it derives its energy from living fruit, works like all batteries.

In this case, the oxidising agent is not the receiver The electron is not a direct receiver of the electrons, but simply causes them to be removed from the zinc and pass through the wire. The reducing agentwhich is the opposite of the oxidising agent, is copper wire because it catalyses the transfer of electrons into hydrogen molecules.

Oxidative phosphorylation

One of the most important biochemical processes for all living animals is oxidative phosphorylation, or the transfer of electrons from nutrients to molecules that provide energy to cells. Typically, the complete breakdown of food is a series of redox reactions, which have many different oxidising agents and electron acceptors. Oxidative phosphorylation is the last step in the process and occurs in the mitochondria of all plants and animals.

During oxidative phosphorylation, a series of proteins embedded in the mitochondrial membrane catalyse oxidation reactions and channel electrons to other proteins. These proteins catalyse reduction reactions of ATP and other energy-providing molecules. This complex series of redox reactions uses many proteins, but works in the same way as the battery does. However, instead of releasing energy in the form of light, the energy is mainly trapped in the formation of new bonds. Some of the energy is released as heat, so the mitochondria are considerably hotter than the rest of the cell.