Chemical Reactions for CBSE Class 12


Chemical reactions for CBSE class 12 students are very interesting part of study. Itcan be seen everywhere in the daily human lives. It commonly happens when two or more compounds are changed into one or more substances due to the reaction between them.

When the chemical reactions produce the substances of chemical compounds or chemical components. In simple words, when the rearrangements are done within the constituent of atoms, the process is commonly called a chemical reaction.

Definition of Chemical Reaction

Chemical reactions are scientific phenomena happen everywhere all around the world. Starting from the metabolism of the human body to the way sunlight light impacts the environment; everything is influenced by the chemical reactions that are constantly taking place. It is defined as the phenomenon happens when the bonds between the molecules are broken and a new bond is formed for the formation of new products.

Physical and chemical changes in the product are result in by chemical reactions help to form a new product. In simpler words, the phenomenon of chemical reactions depends on the temperature, concentration and pressure of the reactants, especially while producing heat, changing colour, and precipitations during the reactions in real-time.

Types of Chemical Reaction

Chemical reactions are segmented into different types, based on the molecules, reactants and other factors like, temperature, heat production, and many more.

Combustion Reaction

This type of reaction happens between an oxidized product and an oxidizer in real-time. During this type of reaction, chemical needs an ample amount of fuel to burn. Combustion takes place in the presence of oxygen and produces carbon dioxide in return. For example, the combustion of magnesium metal is an example of a chemical reaction where two magnesium atoms react to the molecules of oxygen while releasing heat in the process.

Figure 1: Displacement reaction

In the case of the displacement reactions a set of atoms is displaced by the other molecules. This type of reaction takes place when two compounds react with each other and as a result, the cations and anions switch their individual places for the formation of new products. For example, if the reactants are AB+CD in the first place, then the final result is CB+AD in real-time.

Neutralization Reaction

Figure 2: Neutralization reaction

The neutralization reaction is the reactions between acid and base while forming water and salt in a chemical process. Here, the molecules of water are formed due to the combination of OH- ions and the H+ ions during this reaction. For example, when sodium hydrochloride and hydrochloric acid react with each other, water and sodium chloride is formed due to a neutralization reaction.

Decomposition Reaction

Figure 3: Decomposition reaction

Decomposition reaction is a chemical reaction where a single component is broken down into multiple products at a time. The decomposition of calcium carbonate produces CaO, which can be a major example of the decomposition reaction in real-time.

Redox Reaction

The Redox reaction can better be defined as a reduction-oxidation process where electrons are transferred between the chemical species. For example, when zinc and hydrogen react with each other, an electrochemical cell like, redox reaction can be spotted.

Important chemical reactions for CBSE class 12

Sandmeyer Reaction

Figure 4: Sandmeyer reaction

This reaction is commonly seen during the reactions between synthesize aryl or alkyl halides from aryl diazonium salts. It can be used as a substitutionary method during the creation of diazonium salts in real-time instead of the aromatic amino groups.

Gattermann Reaction

In this reaction, chlorine and bromine are used as substituents of the benzene ring while preparing the benzene diazonium salt solution. In this reaction, a similar type of halogen acid can be seen present along with the copper powder in real-time.

Finkelstein Reaction

In the Finkelstein reaction, the alkyl iodides are prepared by a chemical reaction between Nal and alkyl chlorides with the help of a dry acetone.

Wurtz Reaction

This type of reaction is seen when the alkyl halides reacts with sodium using dry ether as solvent as solvent. During this reaction, hydrocarbons are extracted where the double number of carbon atoms can be seen within the alkyl halides. In this reaction, dry ether appears as a principal component.

Kolbe’s Reaction

According to Kolbe’s reaction, phenols generally react with sodium hydroxide in order to produce sodium phenoxide during the reaction. It further reacts with carbon dioxide under an acidic medium and furnishes salicylic acids as a final result.


The phenomenon of chemical reactions takes place when multiple molecules interact with each other for the formation of new products in real-time. Reactions like, Sandmeyer reaction, Gattermann reaction, and Finkelstein reaction are different types of the chemical reactions that help in the formation of new products. These reactions are common in everyday human lives; especially while manufacturing new products for daily life usage.


Q1. Which factors impact on the chemical reactions most during the formation of new products?

Ans. Chemical reactions are deeply impacted by factors like, temperature, concentration, heat, and pressure of the reactants. During the reactions, the reactants face physical changes like heat production, colour change, and precipitation.

Q2. How many molecules are involved when chemical reactions take place in real-time?

Ans. The chemical reactions mostly take place between two or more molecules in real-time. The molecules need to have interactions between them during the formation of new products according to the laws of chemical reactions.

Q3. Which reaction is used in real-time for giving analogous compounds in the conjunction of two aryl groups?

Ans. The Fittig reaction is used during the preparation of aryl halides in dry ether medium along with sodium metal, especially while giving analogous compounds. This mostly helps in making bonds between two aryl groups via conjunction chemical reaction.

Updated on: 17-Apr-2023


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