The key difference between oxidation and reduction is that oxidation refers to the loss of electrons while reduction refers to the gain of electrons.
Chemical reactions between different compounds are called redox reactions if the oxidation states of reactants are different from those of products. Redox is short for reduction-oxidation, which is what occurs in any chemical reaction. While oxidations refer to the loss of electrons, reductions are where the regain of electrons occur. These reactions can be simple or complex, depending upon the process and the atoms involved.
CONTENTS
1. Overview and Key Difference
2. What is Oxidation
3. What is Reduction
4. Side by Side Comparison – Oxidation vs Reduction in Tabular Form
5. Summary
What is Oxidation?
Oxidation can be described as an increase in oxidation number. Therefore, oxidation can be defined as the loss of electrons from an atom, molecule or an ion. This loss of electrons causes the oxidation state of the chemical species to be increased. Since an oxidation reaction releases electrons, there should be an electron-accepting species. Therefore, the oxidation reaction is a half-reaction of a major reaction. The oxidation of a chemical species is given as the change of its oxidation states. Oxidation state is a number with a positive (+) or negative (-) symbol, which indicates the loss or gain of electrons by a particular atom, molecule or an ion.
Figure 01: An Example of the Two Half Reactions: Oxidation and Reduction
In the past, the term oxidation was given the definition “the addition of oxygen to a compound.” This was because oxygen was the only known oxidizing agent at that time. However, this definition is no longer accurate since there are many more oxidation reactions that occur in the absence of oxygen. For example, the reaction between Magnesium (Mg) and Hydrochloric acid (HCl) involves no oxygen, but it is a redox reaction that includes the oxidation of Mg into Mg2+.
What is Reduction?
Reduction can be described as a decrease in oxidation number. Therefore, we can define reduction as the gain of electrons from an atom, a molecule, or an ion. This gain of electrons causes the oxidation state of the chemical species to be decreased. Since a reduction reaction obtains electrons, there should be an electron-donating species. Therefore, the reduction reaction is a half-reaction of a major reaction. The reduction of a chemical species is given as the change of its oxidation states.
In the past, the term reduction was given the definition “the removal of oxygen from a compound.” This was because oxygen was the only known oxidizing agent at that time. However, this definition is no longer accurate since there are many more oxidation reactions that occur in the absence of oxygen.
What is the Difference Between Oxidation and Reduction?
Reduction and oxidation are chemical processes involved in every chemical reaction. These are two opposite reactions. The key difference between oxidation and reduction is that oxidation refers to the loss of electrons while reduction refers to the gain of electrons. While oxidation increases the value of positive (+) sign, reduction increases the value of negative (-) sign.
Summary – Oxidation vs Reduction
Reduction and oxidation are chemical processes involved in every chemical reaction. The key difference between oxidation and reduction is that Oxidation refers to the loss of electrons while reduction refers to the gain of electrons.
Reference:
1. Helmenstine, Anne Marie. “Oxidation Definition and Example in Chemistry.” ThoughtCo, Feb. 12, 2020, Available here.
2. Helmenstine, Anne Marie. “Reduction Definition in Chemistry.” ThoughtCo, Feb. 11, 2020, Available here.
Image Courtesy:
1. “NAD oxidation reduction” By Fvasconcellos 19:44, 9 December 2007 (UTC). w:Image:NAD oxidation reduction.png by Tim Vickers. – Vector version of w:Image:NAD oxidation reduction.png by Tim Vickers (Public Domain) via Commons Wikimedia