Oxidation Number in Redox Reactions

The movement of electrons from one chemical substance to another in chemical processes. Oxidation-reduction reactions, or redox reactions, are electron-transfer reactions. Energy changes in the form of heat, light, and electricity accompany these reactions. The addition of oxygen or hydrogen to various compounds is also involved in the oxidation and reduction reactions.

Contents Table of Contents

• What exactly is oxidation?

• What exactly is reduction?

• The traditional understanding of oxidation and reduction processes

• In terms of electron transfer, oxidation and reduction

• Typical Redox reactions

• How can the Redox reaction be balanced?

• Reduction vs. Oxidation

• Summary

• FAQs

What exactly is oxidation?

Oxidation, according to classical or earlier concepts, is a process that involves the addition of oxygen or any other electronegative element, or the removal of hydrogen or any other electropositive element.

According to electronic concept oxidation is defined as the process in which an atom or ion loses one or more electrons.

What exactly is reduction?

According to the classical or older understanding, reduction is a process that involves the addition of hydrogen or any other electropositive element, as well as the removal of oxygen or any other electronegative element.

According to the electrical idea, reduction is the process of gaining one or more electrons by an atom or ion.

The Classical Concept of Oxidation and Reduction:

Reactions involving oxidation include:

1. Adding oxygen to the mix:

                CO2 = C + O2 (oxidation of carbon)

2. Electronegative element addition:

                FeS = Fe + S (oxidation of Iron)

3. Hydrogen removal:

               2 HBr + S H2S + Br2 (oxidation of sulphide)

4. Electropositive elements must be removed:

                  I2 + 2 KOH + 2 KI + H2O2 (oxidation of iodide)

An oxidising agent is a chemical that causes oxidation to occur. O2, S, Cl2, Br2, and H2O2 are oxidising agents in the instances above.

Reduction reactions include the following steps:

1. Hydrogen injection:

                  2NH3 = N2 + 3 H2 ( reduction of nitrogen)

2. Electropositive element addition:

                  SnCl4 + Hg2Cl2 SnCl2 + 2HgCl2 ( reduction of mercuric chloride)

3. Oxygen depletion

                 ZnO + C vs. Zn + CO (reduction of zinc oxide)

4. Electronegative element removal

                 H2 + 2FeCl3 = 2FeCl2 + 2HCl (reduction of ferric chloride)

A reducing agent is a substance that reduces the amount of something. H2, HgCl2, and C are reducing agents in the cases above.

In terms of electron transfer, oxidation and reduction

• This is the most widely used and relevant definition of oxidation and reduction.

• Oxidation is the loss of electrons in this example, while Reduction is the gain of electrons.

• Oil rig is an excellent mnemonic for remembering this idea.

The reactions of oxidation and reduction are always related. Because electrons are neither generated nor destroyed in chemical reactions, oxidation and reduction must always occur in pairs; one without the other is inconceivable. Magnesium is oxidised by losing two electrons to oxygen, which is reduced by receiving two electrons from magnesium in the mechanism below.

Reduction And Oxidation

Because oxidation and reduction cannot occur separately, they are referred to as “Redox Reactions.” The Oxidizing agent is the reactant that oxidises the other reactants, whereas the Reducing agent is the reactant that reduces them. The question of whether oxidising agents receive or give away electrons is a point of contention.

You can find it out by following the instructions below.

• The other reactants are oxidised by an oxidising agent.

• This must indicate that the oxidising agent is decreasing.

• The loss of electrons is referred to as oxidation (OIL RIG)

• As a result, an oxidising agent must acquire electrons.

Typical Redox Reactions

The following are the three most prevalent redox reactions:

1. Combustion reaction — This is a redox process in which molecular oxygen reacts with a chemical to produce oxygen-containing compounds.

16CO2 (g)+18H2 O 2C8 H18 +25O2

2. Disproportionation reaction – A redox reaction in which only one reactant is reduced and oxidised. An auto-oxidation reaction is another name for it.

ClO3 (aq)+2Cl + 3ClO(aq) (aq)

3. Single replacement reaction – This is a sort of redox reaction in which two elements inside a molecule swap positions. A single displacement reaction is another name for it.

Zn(s) + 2HCl(aq) ZnCl2 (aq) + H2 (g)

How to Maintain Redox Reaction Balance

According to the “Law of Conservation of Mass,” every chemical reaction must be balanced. The following approaches can also be used to balance chemical equations involving oxidation and reduction.

• Method of oxidation number.

• Electron ion technique ( or half reaction method)

Number of oxidations:

Through an example, the various procedures needed in balancing a redox equation using the oxidation approach are presented.

Example: Using the oxidation number method, balance the chemical equation.

                    CuO + NH3 vs Cu + N2 + H2O

Solution:

Step 1: In the skeleton equation, write the oxidation number of each atom

Step 2: Determine which atoms experience oxidation number changes

Step 3: Determine the increase and reduction in oxidation number in relation to the reactant atoms.

Step 4: On the reactant side, calculate the increase and reduction in oxidation number.

Step 5: On both sides of the equation, balance the number of Cu and N atoms.

Step 6: Using the hit-or-miss strategy, balance the H and O atoms.

Reduction vs. Oxidation

Oxidation occurs when a reactant loses electrons during a process. Reduction occurs when a reactant acquires electrons during a reaction. This is a common phenomenon when metals react with acid. Oxidation occurs when a reactant loses electrons during a process. Reduction occurs when a reactant acquires electrons during a reaction. This is a common phenomenon when metals react with acid.

A reduction-oxidation reaction, also known as a redox reaction, is a chemical reaction in which both reduction and oxidation take place at the same time. The electrons are received by the reduced species, whereas they are lost by the oxidised species. Despite its name, an oxidation process does not require the presence of oxygen.

Conclusion

The term oxidation was originally used to describe reactions in which an element interacts with oxygen. The chemical interaction between magnesium metal and oxygen to generate magnesium oxide, for example, is called oxidation of magnesium.

The Latin stem “to lead back” gives rise to the word reduction. As a result, everything in the previously indicated chemical cycle that goes back to magnesium metal suggests reduction. A reaction between magnesium oxide and carbon at 2000 degrees Celsius produces magnesium metal and carbon monoxide, which is an example of magnesium oxide reduction to magnesium metal.

Many organic chemistry processes can be characterised as redox reactions because they include changes in oxidation levels that occur without the transfer of electrons. For example, when wood is burned with molecular oxygen, the oxidation state of carbon atoms in the wood increases, while the oxidation state of oxygen atoms drops as carbon dioxide and water are created. The oxygen atoms are reduced, which means they receive electrons, whereas the carbon atoms are oxidised, which means they lose electrons. As a result, oxygen is the oxidising agent in this process, while carbon is the reducing agent.