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The term “reduction” originally referred to the weight loss that occurs when a metallic ore, such as a metal oxide, is heated to extract the metal. To put it another way, the ore is “reduced” to metal.
Similar to acid-base reactions, oxidation and reduction occur together and cannot occur independently of one another. Moreover, two half-reactions always occur together to make a whole reaction, oxidation and reduction are each called a half-reaction. The acquired or lost electrons are usually explicitly specified when writing half-reactions for the half-reaction to be balanced.
Oxidizing and reducing agents
Reductants and oxidizing agents in redox reactions transfer electrons from the oxidant to the reductant. As a result, the oxidant or oxidizing agent obtains electrons and is reduced, while the reductant or reducing agent loses electrons and is oxidized. A redox pair is a pair of oxidizing and reducing agents that are involved in a particular process.
Oxidisers
Oxidizing agents, oxidants, and oxidisers are substances that can oxidize other substances (causing them to lose electrons). The oxidant (oxidizing agent) takes electrons from another substance and becomes reduced as a result. The oxidizing agent is also known as an electron acceptor since it “accepts” electrons.
Reducers
Reductive or reducing chemicals are called reducing agents, reductants, or reducers because they can reduce other substances (causing them to gain electrons). The reductant (reducing agent) becomes oxidized by transferring electrons to another substance. The reducing agent is sometimes referred to as an electron donor because it donates electrons. Charge transfer complexes between electron donors and electron acceptors can also be formed. In chemistry, there are a lot of different types of reducants.
Significance of redox reactions
Not just in chemistry but also in geology and biology, oxidation-reduction reactions are significant. The Earth’s crust serves as a redox barrier between its reduced metallic core and its oxidizing atmosphere. The Earth’s crust is mainly made up of metal oxides, and the oceans are mostly made up of water, which is hydrogen oxide. The life process of photosynthesis reverses the tendency of practically all surface materials to be oxidized by the environment.
A redox cycle, which functions on a global scale, converts solar radiation into usable energy. By reducing carbon compounds to low oxidation states, photosynthesis turns radiant energy into chemical potential energy, which is recovered either through enzymatic oxidations at ambient temperatures or during burning at high temperatures.
Redox reactions are exemplified by the following examples.
The displacement of metal
A metal atom in a compound (or a solution) gets replaced by an atom of another metal in this reaction. When zinc metal is placed in a copper(II) sulfate solution, for example, copper is deposited:
Zn(s)+ CuSO4(aq) → ZnSO4(aq) + Cu(s)
Free copper metal is liberated when zinc metal displaces the copper(II) ion from copper sulfate solution. Because copper metal has lower energy than zinc due to bonding via its partially full d-orbitals, the reaction is spontaneous and produces zinc.
The ionic equation for this reaction is:
Zn + Cu2+ → Zn2+ + Cu
As two half-reactions, it is seen that the zinc is oxidized:
Zn → Zn2+ + 2 e−
Cu2+ + 2 e− → Cu
Reaction of Decomposition
The breakdown of a molecule into other compounds is what this reaction entails. Various are some examples of these types of reactions:
2NaH → 2Na + H2
2H2O → 2H2 + O2
Na2CO3 → Na2O + CO2
Reaction of Combination
These reactions are the inverse of decomposition processes, in that they combine two chemicals to generate a single compound with the formula A + B AB. Consider the following scenario:
- H2 + Cl2 → 2HCl
- 4 Fe+ 3O2→2Fe2O3
Displacement of Non-Metallic Materials
We can find a hydrogen displacement reaction in this type of reaction, as well as rare oxygen displacement reactions.
Reactions of Disproportion
Disproportionation reactions are those that involve only one reactant being oxidized and reduced.
State of oxidation
The chemical bond’s electron-pair concept inspired the idea of assigning an oxidation state to each of the atoms in a molecule. The nuclei of two or more atoms exert a force of attraction on electrons in the space between them, holding them together within a molecule.
With the help of a few guidelines, oxidation states can be assigned to the most common molecules. First, electrons shared by two atoms of the same element are divided equally; as a result, elements, regardless of their allotropic form, are always in the oxidation state of 0.
Conclusion
To conclude this article we can say that redox reactions is a combination reaction between the oxidising agent and the reducing agent to form a new compound. You can find it occurring at many places in your day to day life, like while respiration redox reaction occurs or when something is burnt (combustion), there also redox reaction occurs and there are other many more such examples.
This article will help you know more about the process and definition of Redox reaction. Also, while going through the article and its FAQ’s, you will get to know the several places where Redox reaction is actually used apart from scientific application.
