Nursing Entrance Exam

Oxidation and Reduction Oxidation is a chemical reaction involving the loss of electrons or the increase of the oxidation state of an element by an atom, molecule, or ion. Reduction is the opposite side of the chemical reaction that involves the gain of an electron, or the decrease in the oxidation state of an element by an ion, molecule, or atom. Originally, the word oxidation was used to refer only to the reaction of an element with oxygen to produce an oxide. Oxygen was the first recognized oxidizing agent, thus the name “oxidation”. The use of the word oxidation later expanded to include reactions with any element or substances that accomplish parallel chemical reactions as that produced by oxygen. Today, oxidation refers to all processes and reactions that involve a loss of electrons or an increase in the oxidation state. The word “reduction” was originally used to refer to all chemical reactions that involved the loss of weight of a metallic ore or metal oxide by heating. When a metal oxide is heated to extract the metal, oxygen is lost as a gas and the overall weight decreases. In time, it was discovered that the metallic ore or element being reduced actually gained some electrons. Today, the chemical application of the term reduction now includes all processes and reactions that involve the gain of electrons or the decrease in the oxidation state. Redox is a word coined from reduction and oxidation. Redox, or oxidation and reduction reactions, comprise chemical reactions where the oxidation state of the atoms involved have been changed. Redox could occur in as simple a chemical process as the oxidation process where carbon is oxidized to produce carbon dioxide (CO2) or the use of hydrogen in the reduction of carbon to produce methane (CH4). Redox could also occur in relatively complex reactions such as oxidization of glucose inside the human body. Redox reactions are primarily associated with the production of oxides with the interaction with oxygen and others, such as oxidation substances. However, redox reactions also include the transfer of electrons during reactions. One peculiar characteristic of redox is that they occur as a matched set; thus, it is not possible to have an oxidation reaction without having a corresponding reduction reaction. This is why oxidation on its own is known as a half reaction. Together, they form the complete reaction because they cannot occur on their own. One side of the reaction loses electrons, while the other side gains electrons during the reaction. In is very important to note that while the loss or gain of electrons usually happens in most oxidation and reduction reactions, chemical reactions where electrons are not gained or lost can still be called oxidation and reduction reactions.

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