NCERT Class 11 Chemistry Chapter 8 Notes Redox Reaction - Download PDF

Redox reactions, commonly known as oxidation-reduction reactions, are fundamental chemical processes in which molecules exchange electrons. Redox reaction is an important topic in NCERT Class 11 Chemistry since this topic has a huge impact on industry and nature. Redox processes include rusting iron, battery performance, and how our bodies break down food. Understanding these reactions is critical for board exams and Competitive exams like JEE and NEET, which typically include questions on oxidation states and balancing equations.

This Story also Contains

1. NCERT Class 11 Chemistry Redox Reaction Notes
2. Redox Reactions in Terms of Electron Transfer Reactions
3. Oxidation Number
4. Balancing of redox reaction
5. Limitation of The Concept of Oxidation Number
6. NCERT Class 11 Notes Chapter-Wise
7. Subject Wise NCERT Exemplar Solutions
8. Subject Wise NCERT Solutions

Redox Reactions are significant in our day-to-day existence. Iron rusts, we burn fuel, and our bodies turn glucose into energy. These responses are important in industries. They help extract metals from ores, are used in electroplating to apply a thin layer of metal to objects, and are necessary for the manufacturing of fuel cells, which are devices that produce electricity.

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NCERT Class 11 Chemistry Redox Reaction Notes

Electrochemical Cell:

It is a device in which the redox reaction is carried out indirectly and decreases in free energy appeals as electrical energy.

Salt Bridge

It is a U-shaped tube filled with agar-agar containing inert electrolytes like potassium chloride or potassium nitrate which does not react with solutions.

Standard hydrogen electrode:

It is also referred to as a reference electrode. The electrode potential of the standard hydrogen electrode is 0.000 volt.

Oxidation and Reduction reactions:

Oxidation is an increase in oxidation number, Whereas Reduction is a decrease in oxidation number in Redox reactions.

Redox Reactions in Terms of Electron Transfer Reactions

Splitting the reaction into two half-reactions clearly suggests the oxidation of Sodium and reduction of Hydrogen. Loss of electrons in any substance means oxidation of that substance occurs whereas gain in any substance signifies the reduction process. Therefore, we can say that the complete reaction itself is a Redox reaction.

2Na(s)+H₂(g)→2NaH(s) is an example of redox change.

The half reaction is:

2Na(s)→2Na⁺(g)+2e⁻

The other half-reaction is:

H₂(g)+2e⁻→2H⁻(g)

Oxidation Number

Oxidation number can be defined as the bond formation of ionic bonds with other heteroatoms and at the same time attaining the charge on that atom.

For example:

The oxidation number for different metal ions:

All alkali metal ions are always having a +1 oxidation state

All alkaline earth metal ions are always having a +2 oxidation state.

Types of Redox reaction:

A redox reaction can be defined as a chemical reaction in which we can see the transfer of electrons occur in between two reactants i.e. one is going to be reduced and the other is going to gain that electron.

a)Decomposition reaction:

This type of reaction involves breaking a compound into other different compounds.

Example:

• 2NaH → 2Na + H₂

b)Combination reaction:

These types of reactions are opposite to decomposition reactions. So the combination of two compounds produces a single product.

Example:

4Fe+ 3O₂→2Fe₂O₃

c)Displacement reaction:

This is a type of reaction where an atom or ion is replaced by another atom or ion according to its reactivity level. It can be categorized into:

• Metal displacement Reaction

• Non-metal displacement Reaction

Metal Displacement reaction:

This type of reaction involves when a metal present in a particular compound is displaced by another metal. This type of reaction can be seen in the metallurgical process where extraction of ores can be done from their respective metals.

For example:

CuSO₄+Zn→Cu+ZnSO₄

Non-Metal Displacement reaction:

This type of reaction involves the displacement of hydrogen and in rare oxygen, displacement can be observed.

Disproportionation reaction:

This is the type of reaction in which reduction and oxidation occur on the same compound or element.

For example:

3Cl2 + 6NaOH→ 5NaCl+NaClO₃ +3H₂O

Balancing of redox reaction

The two ways through which we can balance the redox reaction;

First method: In this method by a change in the oxidation number of oxidizing agent and the reducing agent.

Second method: In this method dividing the redox reaction into two half-reactions in which one is being oxidized and the other is getting reduced.

Redox Titrations on basis of titrations:

In the process of titration, oxidation-reduction reactions occur and are known as redox titration. During the chemical reaction in such a technique transfer of electrons can be seen in the aqueous solution.

The Redox titration can further be classified on the basis of the reagent used in the redox titration.

Sub-Divisions of Redox Titrations

• Permanganate Titrations

• Dichromate Titrations

• Iodometric and Iodometric Titrations

Limitation of The Concept of Oxidation Number

It is not practically possible to apply the classical approach where the oxidation number concept is verified; the reaction is the so-called Redox reaction.

Redox reactions and electrode processes:

A redox couple is defined as when a substance is taking part in the oxidation and reduction process- half-reaction the combination of both oxidized and reduced parts of the substance is present in that reaction.

The electrode potential of a Galvanic cell can be defined as the tendency of losing or gaining the electrodes.

Dependency of electrode potential:

The electrode potential can be dependent upon:

• Nature of the metal,

• The concentration of the ions and

• The temperature of an electrolyte

Significance of NCERT Notes for Chemistry Chapter 7 Notes:

The Redox reactions Class 11 notes focus on the important points regarding the oxidation and reduction reactions. The students can strategize their study plan with the help of these notes. The main goal is to achieve good marks with proper guidance and the best methodological approach. The important Redox reactions and another different reaction mechanism with their example are given so that students didn’t find any difficulty while writing the answers in the CBSE Class 11 Chemistry examinations.

NCERT Class 11 Notes Chapter-Wise

Subject Wise NCERT Exemplar Solutions

Subject Wise NCERT Solutions