Oxidation Reduction

Electron transfer reactions are the chemical processes in which electrons are transferred from one chemical substance to another. These electron-transfer events are called oxidation-reduction reactions or redox reactions in the scientific community. Oxidation and Reduction reactions are followed by energy changes that take the form of heat, light, electricity, and other forms of radiation. The addition of oxygen or hydrogen to various compounds is also a part of the oxidation and reduction reactions.

What is oxidation?

Initially, the word “oxidation” was used to describe processes in which an element interacts with oxygen in the presence of oxygen.

Example: The oxidation of magnesium occurs during the interaction between magnesium metal and oxygen to generate magnesium oxide.

Other examples:

2S(s) + O2 (g) → SO2 (g) CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (l)

Traditional or previous concepts of oxidation define the process as one in which oxygen or any electronegative element is added, while the removal of hydrogen or an electropositive part occurs.

In electronic theory, oxidation is defined as the process by which an atom or ion loses one or more electrons due to a chemical reaction.

What is reduction?

“Reduction” derives from a Latin root meaning “to return to the beginning.” Anything that goes back to magnesium metal is, by definition, a reduction process.

Example: Reducing magnesium oxide to magnesium metal is the interaction between magnesium oxide and carbon at 2000 degrees Celsius, producing magnesium metal and carbon monoxide.

Other examples :

2CH2CH2 (g) + H2 (g) → CH3CH3 (g)

2FeCl3 (aq) + H2 (g) → 2FeCl2 (aq) + 2HCl (aq)

According to the classical or earlier notion, reduction is a process that involves the addition of hydrogen or an electropositive element and the removal of oxygen or any electronegative element.

According to the electronic notion, the reduction is how one atom or an ion receives one or more electrons from another.

Gain and Loss of Oxygen

The addition of oxygen to produce an oxide (oxidation) and removal of oxygen (reduction) are the first conceptions of oxidation and reduction . Every time they appear, it is because they are related. Take, for instance, the combustion of hydrogen.

2H2 + O2   → 2H2O

As a result, hydrogen is oxidised while oxygen is reduced. It is the same pattern followed by the combination of nitrogen and oxygen that happens at high temperatures.

N2 + O2  → 2NO

Nitrogen is oxidised, and oxygen is reduced due to nitric oxide. The oxidation process is the most prevalent in various reactions. Take, for example, the combustion of methane as an illustration.

Carbon and hydrogen are oxidised in the reaction 

CH4 + 2O2  → CO2 + 2H2O

Perhaps it is simpler to understand when you characterise reduction as the acquisition of hydrogen rather than a decrease of oxygen.

The reaction of lead dioxide at high temperatures, on the other hand, looks to be a simple reduction reaction to me.

2PbO2  → 2PbO + O2

Because lead dioxide is reduced, the oxidation of oxygen that occurs due to this reduction may be more easily seen if you think about oxidation in terms of electron loss.

Gain and Loss of Hydrogen

It was initially thought of as adding or removing oxygen in oxidation and reduction. Alternative approaches include describing oxidation as the loss of hydrogen and reduction as the gain of hydrogen in the equation. In explaining the combustion of methane, this provides an advantage over other options.

A chemical reaction between CH4 and oxygen results in CO2 and two hydrogen atoms (H2O).

Using this method, it is apparent that the carbon has been oxidised (has lost all four hydrogen atoms) and that a portion of the oxygen has been decreased (gains hydrogen). Similarly, running methanol over a heated copper gauze to create formaldehyde and hydrogen gas (Hill and Kolb) is another process in which the hydrogen method helps to clarify matters.

CH4 + 2O2  → CO2 + 2H2O

Even though both carbon-containing molecules possess the same amount of oxygen, the creation of formaldehyde is regarded as an oxidation reaction due to the loss of hydrogen. As the two hydrogens that have been released come together, they undergo a reduction process, resulting in the production of H2.

A single molecular product is formed when carbon monoxide reacts with hydrogen, combining the effects of oxidation and reduction in the process.

CO + H2  → CH3OH

Due to the gain of hydrogen, the CO is reduced, and the hydrogen is oxidised due to its interaction with oxygen.

Comparison between  Oxidation and Reduction

Conclusion

Transfer of an electron between two species in a chemical process; we call this an oxidation and reduction reaction (or redox reaction). Redox processes are essential to some of the most fundamental operations of life, such as photosynthesis, respiration, combustion, and corrosion or rusting, to name a few examples.