| Science NCERT Exemplar Solutions (Class 6th to 10th) | ||||||||||||||
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| 6th | 7th | 8th | 9th | 10th | ||||||||||
| Science NCERT Exemplar Solutions (Class 11th) | ||||||||||||||
| Physics | Chemistry | Biology | ||||||||||||
| Science NCERT Exemplar Solutions (Class 12th) | ||||||||||||||
| Physics | Chemistry | Biology | ||||||||||||
Class 12th Chemistry NCERT Exemplar Solutions
1. Solid State
This chapter delves into the **solid state of matter**, exploring the properties and structures of solids based on particle arrangement. It classifies solids into crystalline and amorphous types. Crystalline solids are further studied based on their unit cells (simple cubic, BCC, FCC) and packing efficiency (close packing in 1D, 2D, 3D). Concepts like coordination number, density calculations, and different types of crystalline solids (ionic, covalent, molecular, metallic) are discussed. The chapter also covers **defects** in solids (stoichiometric, non-stoichiometric) and their influence on electrical and magnetic properties (conductors, insulators, semiconductors, ferro/ferrimagnetism).
2. Solutions
This chapter focuses on **solutions**, which are homogeneous mixtures. It discusses various ways to express the **concentration** of solutions quantitatively (molarity $\textsf{M}$, molality $\textsf{m}$, mole fraction $\chi$, mass percentage, ppm). **Raoult's Law** for volatile and non-volatile solutes is central, explaining ideal and non-ideal solutions. The chapter details **colligative properties**, which depend solely on the number of solute particles: relative lowering of vapour pressure, elevation of boiling point ($\Delta \textsf{T}_\text{b}$), depression of freezing point ($\Delta \textsf{T}_\text{f}$), and **osmotic pressure** ($\pi = \textsf{CRT}$). Abnormal molar masses and the **Van't Hoff factor** are also covered for associating/dissociating solutes.
3. Electrochemistry
**Electrochemistry** explores the interconversion of chemical and electrical energy. This chapter introduces **electrochemical cells**, including **Galvanic cells** (producing electricity from spontaneous reactions) and **Electrolytic cells** (using electricity for non-spontaneous reactions). Concepts like electrode potential, **standard electrode potential** ($E^\circ$), and the **Nernst equation** are explained for calculating cell potential. **Electrolytic conductivity** ($\kappa$), molar conductivity ($\Lambda_\text{m}$), and their variation with concentration are discussed, along with **Kohlrausch's Law**. Electrolysis, **Faraday's laws**, different types of batteries (primary, secondary), fuel cells, and **corrosion** and its prevention are also covered, linking chemical reactions to electrical phenomena.
4. Chemical Kinetics
**Chemical kinetics** studies the **rate** of chemical reactions and the factors influencing it. This chapter defines reaction rate and discusses how it is affected by concentration, temperature, pressure, catalyst, and surface area. The **rate law**, rate constant ($\textsf{k}$), **order of reaction**, and molecularity are introduced. Integrated rate equations for zero, first, and sometimes second-order reactions are derived, along with the concept of **half-life** ($t_{1/2}$). The **collision theory** and the concept of **activation energy** ($E_\text{a}$) are explained to understand reaction mechanisms. The **Arrhenius equation** ($\textsf{k} = \textsf{A}e^{-\textsf{E}_\text{a}/\textsf{RT}}$) relates temperature and rate constant.
5. Surface Chemistry
This chapter explores phenomena occurring at interfaces, such as surfaces. It discusses **adsorption**, the accumulation of molecular species on the surface (adsorbent) from the bulk (adsorbate), distinguishing between physisorption and chemisorption. Factors affecting adsorption and the **Freundlich adsorption isotherm** are covered. **Catalysis**, the process where a substance (catalyst) changes reaction rate, is discussed, including homogeneous and heterogeneous catalysis, shape-selective catalysis (zeolites), and enzyme catalysis. The chapter also introduces **colloids**, heterogeneous systems with particles dispersed in a medium, describing their classification, preparation, properties (Tyndall effect, Brownian movement, electrophoresis), and applications, including **emulsions**.
6. General Principles And Processes Of Isolation Of Elements
This chapter focuses on **metallurgy**, the science and technology of extracting metals from their ores and refining them. It discusses the occurrence of metals (minerals, ores) and the general steps involved in **extracting elements**: **concentration** of ore (removing gangue), **conversion** of concentrated ore into an easily reducible form (usually oxide), and **reduction** of the oxide to the metal (e.g., by carbon, CO, or electrolysis). Different methods of refining metals (e.g., distillation, liquation, electrolysis, zone refining, vapour phase refining) are explained, illustrating these principles with the extraction of common metals like Aluminium ($\textsf{Al}$), Iron ($\textsf{Fe}$), Copper ($\textsf{Cu}$), and Zinc ($\textsf{Zn}$).
7. The P-Block Elements
This chapter provides a detailed study of the chemistry of the **p-block elements**, located in Groups 15 to 18 of the Periodic Table (excluding Helium). It discusses their electronic configurations, oxidation states, and trends in physical and chemical properties across periods and down groups. The chemistry of specific groups and important compounds is explored, including Nitrogen and Phosphorus (Group 15), Oxygen and Sulfur (Group 16), Halogens (Group 17), and Noble Gases (Group 18). Properties of compounds like Ammonia ($\textsf{NH}_3$), Nitric Acid ($\textsf{HNO}_3$), Sulfuric Acid ($\textsf{H}_2\textsf{SO}_4$), and Halogen compounds are covered, highlighting the diverse nature of this block.
8. The D-Block And F-Block Elements
This chapter focuses on the chemistry of the **transition elements** (d-block) and **inner transition elements** (f-block), namely **Lanthanoids** and **Actinoids**. It discusses their electronic configurations and general characteristics of transition elements such as metallic nature, variable oxidation states, formation of **coloured ions**, catalytic properties, and magnetic properties. The preparation and properties of important compounds like Potassium Permanganate ($\textsf{KMnO}_4$) and Potassium Dichromate ($\textsf{K}_2\textsf{Cr}_2\textsf{O}_7$) are studied. The **Lanthanoid contraction** and its consequences are explained, highlighting the unique characteristics and uses of these elements, which are often found in various alloys and catalysts.
9. Coordination Compounds
This chapter introduces **coordination compounds** or complexes, containing a central metal atom or ion surrounded by ligands via coordinate covalent bonds. It discusses **Werner's theory**, defines key terms like coordination number, ligand types, chelation, and oxidation state. The **IUPAC nomenclature** for naming these compounds is covered. Different types of **isomerism** (structural and stereoisomerism) are discussed. Bonding in coordination compounds is explained using Valence Bond Theory (VBT) and **Crystal Field Theory (CFT)** to account for their structure, bonding, magnetic properties, and colour. Their applications in various fields, including biological systems (e.g., chlorophyll, haemoglobin) and industry, are also highlighted.
10. Haloalkanes And Haloarenes
This chapter deals with organic compounds containing halogen atoms attached to alkyl groups (**haloalkanes**) or aryl groups (**haloarenes**). It covers their nomenclature, classification, and methods of preparation (e.g., from alcohols, hydrocarbons). Physical properties (boiling points, solubility) and characteristic **chemical reactions** are discussed. For haloalkanes, **nucleophilic substitution reactions** ($\textsf{S}_\text{N}1$ and $\textsf{S}_\text{N}2$ mechanisms) and elimination reactions are key. Preparation and **electrophilic substitution reactions** of haloarenes are explained, highlighting the difference in reactivity compared to haloalkanes. The chapter also briefly mentions the uses and environmental effects of some polyhalogen compounds like DDT.
11. Alcohols, Phenols And Ethers
This chapter explores the chemistry of organic compounds containing the hydroxyl (-OH) functional group – **alcohols** (aliphatic) and **phenols** (aromatic) – and the ether linkage (-O-) – **ethers**. It covers their nomenclature, methods of preparation (e.g., from alkenes, carbonyl compounds), physical properties (influenced by hydrogen bonding), and characteristic chemical reactions. The **acidic nature** of alcohols and phenols is compared. Reactions like esterification, oxidation, dehydration, and electrophilic substitution (for phenols) are discussed. Preparation and reactions of ethers, such as cleavage reactions and electrophilic substitution (for aromatic ethers), are also studied, highlighting the diverse reactions of these oxygen-containing functional groups.
12. Aldehydes, Ketones And Carboxylic Acids
This chapter focuses on organic compounds containing the **carbonyl group** ($\textsf{C=O}$) – **aldehydes** and **ketones** – and the **carboxyl group** ($\textsf{-COOH}$) – **carboxylic acids**. It covers their nomenclature, structure, methods of preparation (e.g., oxidation of alcohols, ozonolysis), physical properties, and characteristic chemical reactions. Key reactions for aldehydes and ketones include **nucleophilic addition**, oxidation, reduction, **Aldol condensation**, and **Cannizzaro reaction**. For carboxylic acids, the **acidic nature** is discussed, along with reactions like esterification, reduction, and reactions involving the $\alpha$-hydrogen (**HVZ reaction**). The uses of these important classes of organic compounds are also highlighted.
13. Amines
**Amines** are organic compounds containing nitrogen, derived from ammonia ($\textsf{NH}_3$) by replacing hydrogen atoms with alkyl or aryl groups. This chapter covers their nomenclature, classification (primary $1^\circ$, secondary $2^\circ$, tertiary $3^\circ$), and methods of preparation (e.g., reduction of nitro compounds, ammonolysis of alkyl halides, Gabriel phthalimide synthesis, Hoffmann bromamide degradation). Their physical properties (like boiling points, basic strength) and important chemical reactions are discussed. A key aspect is their **basic nature** ($\textsf{K}_\text{b}$ values) and reactions like alkylation, acylation, reactions with nitrous acid, and the **Hinsberg test** for distinguishing primary, secondary, and tertiary amines. Reactions involving **diazonium salts** are also introduced, significant in organic synthesis.
14. Biomolecules
This chapter focuses on the essential organic molecules found in living organisms, crucial for biological processes. It covers the structure and function of the four major classes of **biomolecules**: **Carbohydrates** (energy sources, structure - e.g., glucose, sucrose, starch, cellulose), **Proteins** (polymers of amino acids, diverse functions - enzymes, antibodies, structure), **Nucleic Acids** (DNA and RNA - carriers of genetic information), and **Lipids** (fats, phospholipids, steroids). The chapter also discusses the role of **Enzymes** as biological catalysts, introduces **Vitamins** and **Hormones**, highlighting the complex interplay of these molecules in sustaining life and metabolism.
15. Polymers
This chapter introduces **polymers**, which are large macromolecules formed by linking together many small repeating units called monomers. It covers their classification based on source (natural, synthetic), structure (linear, branched, cross-linked), mode of polymerization (**addition** and **condensation**), and molecular forces (elastomers, fibres, thermoplastics, thermosetting plastics). Different types of polymerization mechanisms are discussed. The structure, properties, and uses of important synthetic polymers like polyethylene, PVC, Teflon, polyacrylonitrile, nylon-6,6, Bakelite, and natural rubber are explained. The chapter also touches upon **biodegradable polymers** and their growing importance in addressing plastic waste environmental issues, relevant in the Indian context.
16. Chemistry In Everyday Life
This chapter explores the application of chemical principles and compounds in various aspects of our daily lives. It discusses the chemistry of **drugs**, classifying them based on pharmacological action (e.g., analgesics, antipyretics, antacids, tranquillizers, antibiotics, antiseptics, disinfectants). The chemistry of **food additives** like preservatives, artificial sweetening agents, and antioxidants is explained. The chapter also covers **cleansing agents**, detailing the structure and action of **soaps** and **synthetic detergents**, highlighting their mechanism of cleaning and environmental considerations. Understanding this reveals how chemistry plays a vital role in health, food, and sanitation.
Sample Paper I
This entry provides **Sample Paper I**, designed as a crucial practice resource for students preparing for Class 12th Chemistry examinations based on the NCERT Exemplar Solutions. It contains a comprehensive set of questions covering concepts, reactions, calculations, and problem-solving techniques from Chapters 1 through 16. Attempting this sample paper under timed conditions allows students to assess their overall preparedness, identify areas of weakness, improve speed and accuracy, and become familiar with the exam pattern and question types, enhancing confidence for the actual examination.
Sample Paper II
This entry presents **Sample Paper II**, offering a second valuable opportunity for students to practice and reinforce their understanding of the entire Class 12th Chemistry syllabus covered in the NCERT Exemplar Solutions (Chapters 1-16). This paper provides a fresh set of varied questions, allowing students to encounter different problem-solving scenarios and refine their approach. Engaging with both sample papers is highly recommended for thorough revision, solidifying conceptual clarity, improving application skills, and optimizing exam performance in Chemistry.