NCERT Exemplar Class 12 Chemistry Solutions

Chemistry - Exemplar

NCERT Exemplar Class 12 Chemistry Solutions enable you to access chapter-wise solved questions for all the topics of the textbook. Preparation from NCERT Exemplar Class 12 Chemistry textbook helps you develop understanding of each topic from the scratch and provide you with an ample amount of practice.

Although the course book of NCERT is considered as the best study material from the exam point of view, solving questions from exemplar textbook will be an added advantage. This textbook contains a wide range of questions of varying difficulty level that enhances your level of understanding and accuracy.

NCERT Exemplar Solutions for Class 12 Chemistry

NCERT Class 12 Chemistry Exemplar Solutions (Chapter-wise Description)

Chapter 1: Solid States

In this chapter, you will first study the general properties of the solid state. As you already know, solids have a fixed shape and volume because their constituent particles vibrate about their mean position. Besides, they also have strong intermolecular forces acting between their particles. 

Further, you will classify amorphous and crystalline solids based on their shape, melting point, cleavage property, the heat of fusion, nature, and order of arrangement. Some important terminologies of this chapter include crystal lattice, unit cell, lattice point, Bravais lattice, etc. 

Moving forward, we will discuss the unit cell, which can either be primitive or centred based on the location of their particles. A primitive unit cell contains particles at its corner positions. The centred unit cell has its particles present at the body centre. 

Finally, you will learn about the close-packing of particles in two different lattices, including hexagonal close-packed and cubic close-packed. Also, learn about various imperfections in solids and their magnetic properties. 

List of Topics in Chapter-1 “Solid States”

    1. General Characteristics of Solid State
    2. Amorphous and Crystalline Solids
    3. Classification of Crystalline Solids
      1. Molecular Solids
      2. Ionic Solids
      3. Metallic Solids
      4. Covalent/ Network Solids
    4. Crystal Lattices and Units Cells
      1.  Primitive and Centered Unit Cells
    5. Number of Atoms in a Unit Cell
      1. Primitive Cubic Unit Cell
      2. Body-Centered Cubic Unit Cell
      3. Face-Centred Cubic Unit Cell
    6. Close Packed Structures
    7. Packing Efficiency
      1. Packing Efficiency in hcp and ccp Structures
      2. Efficiency of Packing in Body Centered Cubic Structures
      3. Packing Efficiency in Simple Cubic Lattice
    8. Calculations Involving Unit Cell Dimensions
    9. Imperfections in Solids
      1. Types of Point Defects
    10. Electrical Properties
      1. Conduction of Electricity in Metals
      2. Conduction of Electricity in Semiconductors

Chapter 2: Solutions

Chapter-2 Solutions discusses that you can obtain a solution by mixing two or more substances with each other. These are classified into three phases, which are solid, liquid and gas. 

Further, you will learn to measure the concentration of a solution in terms of percentage, mole fraction, molarity and molality. Next comes the two important laws of this chapter, including Henry’s law and Raoult’s law. Henry stated that the solubility of a gas depends proportionally on the partial pressure of the gas. 

Raoult found out that you can lower the vapor pressure of the solvent by adding a non-volatile solute in the solution. In the second half of this chapter, you will study various properties of solutions, which rely on the number of factors. These properties of solutions are called colligative properties. 

At the end of the NCERT Exemplar Class 12 Chemistry Chapter-2, you will study how a solute can be dissociated by Van’t Hoff factor. The complete list of topics covered in this chapter is as follows. 

List of Topics in Chapter-2 “Solutions”

  1. Type of Solutions
  2. Expressing Concentration of Solutions
  3. Solubility
    1. Solubility of a Solid in a Liquid
    2. Solubility of a Gas in a Liquid
  4. Vapour Pressure of Liquid Solutions
    1. Vapour Pressure of Liquid-Liquid Solutions
    2. Raoult’s Law as a Special Case of Henry’s Law
    3. Vapour Pressure of Solutions of Solids in Liquids
  5. Ideal and Non-Ideal Solutions
    1. Ideal Solutions
    2. Non-ideal Solutions
  6. Colligative Properties and Determination of Molar Mass
    1. Relative Lowering of Vapour Pressure
    2. Elevation of Boiling Point
    3. Depression of Freezing Point 
    4. Osmosis and Osmotic Pressure
    5. Reverse Osmosis and Water Purification
  7. Abnormal Molar Masses

Chapter 3: Electrochemistry

Let us first understand how an electrochemical cell is made. It comprises of two metallic electrodes that are immersed in an electrolytic solution. An electrochemical cell is of two types- galvanic and electrolytic. 

Next, you will learn to differentiate between a galvanic cell and electrolytic cell. In a galvanic cell, the chemical energy is converted into an electrical energy, whereas in an electrolytic cell, a non-spontaneous redox reaction takes place with the help of electrical energy. 

As you proceed, you will study the formula of standard electrode potential, which will help you find the difference of the standard potentials of cathode and anode. Further, find out the factors on which conductivity and molar conductivity of an electrolytic solution depends. 

Nearing the conclusion of Chapter-3, read about the “law of independent migration of ions” and its applications. Two most useful forms of galvanic cells are batteries and fuel cells. When a metal corrodes, it is said to have undergone the electrochemical process. 

List of Topics in Chapter-3 “Electrochemistry”

    1. Electrochemical Cells
    2. Galvanic Cells
      1. Measurement of Electrode Potential
      2. Nernst Equation
        1. Equilibrium Constant from Nernst Equation
        2. Electrochemical Cell and Gibbs Energy of the Reaction
        3. Conductance of Electrolytic Solutions
          1. Measurement of the Conductivity of Ionic Solutions
          2. Variation of Conductivity and Molar Conductivity with Concentration
        4. Electrolytic Cells and Electrolysis
          1. Products of Electrolysis
          2. Batteries
        5. Corrosion

Chapter 4: Chemical Kinetics

Chapter-4 “Chemical Kinetics” is about chemical reactions, which takes place with respect to the effect of various variables, reorientation of atoms and formation of intermediates, etc. To begin with, the rate of a reaction can be defined as the decrease in the concentration of reactants on the increase in the concentration of products per unit time. 

Factors affecting the rate of a reaction, include the concentration of reactants, catalyst and temperature. Mathematically, it can be represented using the rate law. To find the order of a reaction, add the powers of concentration of terms for different reactants. 

Apart from the order of a reaction, you can also determine the rate constant from the rate law. In the latter half of this chapter, you will learn to calculate the activation energy, which can be found by the energy difference between the activated complex and the reactant molecules. 

List of Topics in Chapter-4 “Chemical Kinetics”

  1. Rate of a Chemical Reaction
  2. Factors Influencing the Rate of a Reaction
    1. Dependence of Rate on Concentration
    2. Rate Expression and Rate Constant
    3. Order of a Reaction
    4. Molecularity of a Reaction
  3. Integrated Rate Equations
    1. Zero Order Reactions
    2. First Order Reactions
    3. Half-Life of a Reaction
  4. Temperature Dependence of the Rate of a Reaction
    1. Effect of Catalyst
  5. Collision Theory of Chemical Reactions

Chapter 5: Surface Chemistry

This chapter focuses on the chemical reactions that take place on the surface than in bulk. Adsorption is one such process in which molecules of a substance get attracted and retained on the surface of a solid. The substances that are collected on the surface are known as adsorbates ,whereas the surface on which adsorption takes place is called adsorbent. 

Next, study the differences between physisorption and chemisorption. In the case of physisorption, adsorbate and adsorbent are held together by weak van der Waals forces. Chemisorption, on the other hand, refers to an  interaction between adsorbate and adsorbent by the strong chemical bond. 

Let us next discuss adsorption isotherm, which shows the relationship between the extent of adsorption and pressure of the gas at a constant temperature. Further, know the role of a catalyst in a chemical reaction. 

A catalyst is involved in increasing the rate of the reaction without being consumed in it. This process is called catalysis. It is of two types- homogeneous and heterogeneous. Nearing the conclusion, enhance your understanding of colloidal solutions and emulsions.

List of Topics in Chapter 5 “Surface Chemistry”

  1. Adsorption
    1. Distinction between Adsorption and Absorption
    2. Mechanism of Adsorption
    3. Types of Adsorption
    4. Adsorption Isotherms
    5. Adsorption from Solution Phase
    6. Applications of Adsorption
  2. Catalysis
    1. Homogeneous and Heterogeneous Catalysis
    2. Adsorption Theory of Heterogeneous Catalysis
    3. Shape-Selective Catalysis by Zeolites
    4. Enzyme Catalysis
    5. Catalysts in Industry
  3. Colloids
  4. Classification of Colloids
    1. Classification Based on Physical State of Dispersed Phase and Dispersion Medium
    2. Classification Based on the Nature of Interaction between Dispersed Phase and Dispersion Medium
    3. Classification Based on the Type of Particles of the Dispersed Phase, Multimolecular, Macromolecular and Associated Colloids 
  5. Preparation of Colloids
  6. Purification of Colloidal Solutions 
  7. Properties of Colloidal Solutions
    1. Emulsions
    2. Colloids Around Us

Chapter 6: General Principle and Processes of Isolation of Elements

Know about metallurgy and modern metallurgical methods that have a major contribution in shaping up the industries. Next, this chapter discusses the different applications of metals and the process of their extraction from the ores. 

During the process of extraction of metals, there exist various impurities that can be removed to a certain extent, with the help of concentration steps. Unlike other methods, refining helps you obtain pure metals. Refining depends upon the differences in the properties of the metal and the number of impurities. 

To sum up, you will learn about occurrence, common method of extraction, and purification process of four metals- aluminium, copper, iron and zinc. Important terminologies of NCERT Class 12 Chemistry Exemplar Chapter-6 include minerals, ores, calcination, roasting, refining, and benefaction. 

List of Topics in Chapter 6 “General Principle and Processes of Isolation of Elements”

  1. Occurence of Metals
  2. Concentration of Ores
    1. Hydraulic Washing
    2. Magnetic Separation
    3. Froth Floatation Method
    4. Leaching
  3. Extraction of Crude Metal from Concentrated Ore
  4. Thermodynamic Principles of Metallurgy
    1. Applications
  5. Electrochemical Principles of Metallurgy
  6. Oxidation Reduction
  7. Refining
  8. Uses of Aluminium, Copper, Zinc

Chapter 7: The p-block Elements

In this chapter, you will first study the general trends in the chemistry of elements of groups 15, 16, 17 and 18. Moving forward, know the process of preparation, characteristics and applications of di-nitrogen and phosphorus. 

Also know about the preparation techniques, characteristics, and applications of dioxygen. In the previous class, you have read about group 13 and 14 elements. The remaining groups, including group 15 to 18, will be discussed in this chapter, along with their valence shell electronic configuration. 

In the latter half of the chapter, develop an understanding regarding the resonating structures that are characterized by the presence of multiple bonds. Know about large scale preparation of ammonia with the help of Haber’s process. Contact process, on the other hand, is useful for the preparation of sulphuric acid. 

Group 17 of the periodic table consists of halogens, including Fluorine, Chlorine, Bromine, Iodine, and Astatine. Finally, study the group 18 elements, which are also called noble gases. 

List of Topics in Chapter 7 “The p-block Elements”

  1. Group 15 Elements
    1. Occurrence
    2. Electronic Configuration
    3. Atomic and Ionic Radii
    4. Ionisation Enthalpy
    5. Electronegativity
    6. Physical Properties
    7. Chemical Properties
  2. Dinitrogen
  3. Ammonia
  4. Oxides of Nitrogen
  5. Nitric Acid
  6. Phosphorus- Allotropic Forms
  7. Phosphine
  8. Phosphorus Halides
    1. Phosphorus Trichloride
    2. Phosphorus Pentachloride
  9. Oxoacids of Phosphorus
  10. Group 16 Elements
    1. Occurrence
    2. Electronic Configuration
    3. Atomic and Ionic Radii
    4. Ionisation Enthalpy
    5. Electron Gain Enthalpy
    6. Electronegativity
    7. Physical Properties
    8. Chemical Properties
  11. Dioxygen
  12. Simple Oxides
  13. Ozone
  14. Sulphur-Allotropic Forms
  15. Sulphur Dioxide
  16. Oxoacids of Sulphur
  17. Sulphuric Acid
  18. Group 17 Elements
    1. Occurrence
    2. Electronic Configuration
    3. Atomic and Ionic Radii
    4. Ionisation Enthalpy
    5. Electron Gain Enthalpy
    6. Electronegativity
    7. Physical Properties
    8. Chemical Properties
  19. Chlorine
  20. Hydrogen Chloride
  21. Oxoacids of Halogens
  22. Interhalogen Compounds


Chapter 8: The d- and f-block Elements

The groups 3-12 of the periodic table are part of d-block elements. The f-block elements of the periodic table are placed at the bottom, in which 4f and 5f orbitals are progressively filled. Proceeding further, study about transition elements that exhibit various metallic properties, such as ductility, malleability, electrical conductivity and high tensile strength. 

Transition elements possess strong interatomic bonding because their melting and boiling points are high. These elements widely differ in their chemical behaviour. The f-block of the periodic table is a collection of inner transition elements, lanthanoids, and actinoids. 

The last segment of Chapter 8 informs about useful applications of the d- and f-block elements and their compounds. 

List of Topics in Chapter 8 “The d- and f-block Elements”

  1. Position in the Periodic Table
  2. Electronic Configurations of the d-Block Elements Elements
  3. General Properties of the Transition Elements Elements
    1. Physical Properties
    2. Variation in Atomic and Ionic Sizes of Transition Metals
    3. Ionisation Enthalpies
    4. Oxidation States
    5. Trends in the Standard Electrode Potentials
    6. Magnetic Properties
    7. Formation of Coloured Ions
    8. Formation of Complex Compounds
    9. Catalytic Properties
    10. Formation of Interstitial Compounds
    11. Alloy Formation
  4. Some Important Compounds of Transition Elements 
  5. The Lanthanoids
    1. Electronic Configurations
    2. Atomic and Ionic Sizes
    3. Oxidation States
    4. General Characteristics
  6. The Actinoids
  7. Some Applications of d- and f-Block Elements

Chapter 9: Coordination Compounds

Before we delve deeper into the concepts of coordination compounds, let us first familiarize ourselves with the basics. Coordination compounds are complex compounds in which metal atoms join with a number of anions or neutral molecules by sharing electrons. 

The opening topic of Chapter-9 discusses the postulates of Werner’s theory of coordination compounds. Next, you will come across a few important terminologies that will help you strengthen your base concepts of inorganic chemistry. These definitions include coordination entity, ligand, coordination number, coordination sphere, oxidation number, etc. 

Having understood the basic terminologies, you will next learn how to name coordination compounds. You can name a coordination entity based on the guidelines provided by the International Union of Pure and Applied Chemistry. In the second half of this chapter, you will also learn the formulas and names of mononuclear coordination compounds.

Next comes the two important theories- valence bond theory (VBT) and the crystal field theory (CFT). Lastly, know about different applications of coordination compounds. It finds its applications in analytical chemistry, medicinal chemistry and metallurgical processes. 

List of Topics in Chapter 9 “Coordination Compounds”

  1. Werner’s Theory of Coordination Compounds 
  2. Definitions of Important Terms Pertaining to Coordination Compounds
  3. Nomenclature of Coordination Compounds
    1. Formulas of Mononuclear Coordination Entities
    2. Naming of Mononuclear Coordination Compounds
  4. Isomerism in Coordination Compounds
    1. Geometric Isomerism
    2. Optical Isomerism
    3. Linkage Isomerism
    4. Coordination Isomerism
    5. Ionisation Isomerism
    6. Solvate Isomerism
  5. Bonding in Coordination Compounds
    1. Valence Bond Theory
    2. Magnetic Properties of Coordination Compounds
    3. Limitations of Valence Bond Theory
    4. Crystal Field Theory
    5. Colour in Coordination Compounds
    6. Limitations of Crystal Field Theory
  6. Bonding in Metal Carbonyls
  7. Importance and Applications of Coordination Compounds

Chapter 10: Haloalkanes and Haloarenes

The tenth chapter introduces you to haloalkanes and haloarenes, which are characterized by the bond formation of halogens with sp3 and sp2 hybridized carbon atoms, respectively. After understanding the formation of these compounds, you will learn to classify them based on the number of halogen atoms.

As you have already learnt to classify halogens, you will find it easy to name halogenated compounds. The next topic will cover the reactions involved in the preparation of haloalkanes and haloarenes. Later, study the physical properties such as melting and boiling point, density, solubility, etc. 

As you proceed, you will find that haloalkanes can undergo three different types of reactions, including nucleophilic substitution, elimination reaction, and reaction with metals. Next, you will get to understand the reaction mechanism of haloarenes in three different ways. 

The final topic of NCERT Class 12 Chemistry Exemplar Chapter-10 will introduce you to different types of polyhalogen compounds. These include chloroform, dichloromethane, carbon tetrachloride, freon, iodoform and DDT. 

List of Topics in Chapter 10 “Haloalkanes and Haloarenes”

    1. Classification
      1. On the Basis of Number of Halogen Atoms
      2. Compounds Containing sp3 C-X Bond
      3. Compounds Containing sp2 C-X Bond
    2. Nomenclature
    3. Nature of C-X Bond
    4. Methods of Preparation of Haloalkanes
      1. From Alcohols
      2. From Hydrocarbons
    5. Preparation of Haloarenes
    6. Physical Properties
    7. Chemical Reactions
      1. Reactions of Haloalkanes
      2. Reactions of Haloarenes
    8. Polyhalogen Compounds
      1. Dichloromethane
      2. Trichloromethane
      3. Triiodomethane
      4. Tetrachloromethane
      5. Freons
      6. p,p’-Dichlorodiphenyltrichloroethane (DDT)

Chapter 11: Alcohols, Phenols, and Ethers

Chapter-11 “Alcohols, Phenols, and Ethers” begins with the classification of alcohols and phenols. Alcohols and phenols can be differentiated based on the number of hydroxyl groups and hybridisation of the carbon atom. 

When it comes to preparation of alcohols, those compounds can be prepared in two different ways. Firstly, we can prepare them by reacting alkenes with water and acid. Alternatively, hydroboration-oxidation reaction comes to use for obtaining alcohol. 

Proceeding further, this chapter explains the substitution of the halogen atom in haloarenes and sulphonic acid by -OH group for preparation of phenols. Alternatively, phenols can be prepared by hydrolysis of diazonium salts, and cumene in industries. 

As you approach the middle segment of this chapter, you will study that both alcohols and phenols are acidic in nature. The presence of electron-withdrawing groups in phenols increases its acidic strength. While the presence of electron releasing groups decrease reduces the acidic strength. 

List of Topics in Chapter 11 “Alcohols, Phenols, and Ethers”

  1. Classification
    1. Alcohols— Mono, Di, Tri or Polyhydric alcohols
    2. Phenols— Mono, Di and trihydric phenols
    3. Ethers
  2. Nomenclature
  3. Structure of Functional Groups
  4. Alcohols and Phenols
    1. Preparation of Alcohols
    2. Preparation of Phenols
    3. Physical Properties
    4. Chemical Reactions
  5. Some Commercially Important Alcohols
  6. Ethers
    1. Preparation of Ethers
    2. Physical Properties
    3. Chemical Reactions

Chapter 12: Aldehydes, Ketones, and Carboxylic Acids

The twelfth chapter of NCERT Class 12 Chemistry Exemplar talks about the organic compounds containing carbon-oxygen double bond called carbonyl group. First, you will learn the nomenclature of aldehydes, ketones and carboxylic acids. 

Next, you will study the structures of the carbonyl groups and methods of their preparation. As you dig deep into this chapter, learn to correlate physical properties and chemical reactions of these groups. 

The common method used for the preparation of aromatic ketones is the Friedel-Crafts acylation. Using the Wolff-Kishner reduction process, aldehydes and ketones can be reduced to a methylene group. 

Nearing the conclusion, you will study various factors affecting the acidity of carboxylic acids and their reactions. The applications of aldehydes, ketones and carboxylic acids have also been discussed at the end. 

List of Topics in Chapter 12 “Aldehydes, Ketones, and Carboxylic Acids”

  1. Nomenclature and Structure of Carbonyl Group
    1. Nomenclature
    2. Structure of the Carbonyl Group 
  2. Preparation of Aldehydes and Ketones
    1. Preparation of Aldehydes and Ketones
    2. Preparation of Aldehydes
    3. Preparation of Ketones
  3. Physical Properties
  4. Chemical Reactions
  5. Uses of Aldehydes and Ketones
  6. Nomenclature and Structure of Carboxyl Group
    1. Nomenclature
    2. Structure of Carboxyl Group
  7. Methods of Preparation of Carboxylic Acids
  8. Chemical Reactions
    1.  Reactions Involving Cleavage of O–H Bond
    2. Reactions Involving Cleavage of C–OH Bond
    3. Reactions Involving –COOH Group
    4. Substitution Reactions in the Hydrocarbon Part
  9. Uses of Carboxylic Acids

Chapter 13: Amines

To begin with, amines can be obtained from ammonia by the replacement of hydrogen atoms with alkyl or aryl group. Amines are classified into primary, secondary and tertiary amines based on the number of hydrogen atoms replaced with ammonia. 

The common characteristic among all three types of amines is that each of them has one unshared electron pair on the nitrogen atom. Due to this, they behave as Lewis bases. Generally, amines are obtained from nitro compounds such as amides, halides, imides, etc. There exist hydrogen bonding within these compounds which influence their physical properties. 

In the end, this chapter will unfold the method of preparation of diazonium salts and their importance in the synthesis of a series of aromatic compounds. Aryldiazonium salts that are obtained from arylamines also undergo replacement of the diazonium group. 

List of Topics in Chapter 13 “Amines”

  1. Structure
  2. Classification
  3. Nomenclature
  4. Preparation of Amines
  5. Physical Properties
  6. Chemical Reactions
  7. Method of Preparation of Diazonium Salts
  8. Importance of Diazonium Salts in Synthesis of Aromatic Compounds

Chapter 14: Biomolecules

In this chapter, you will first read about carbohydrates and its classification. They can be categorised into three types- monosaccharides, disaccharides and polysaccharides. The following topic discusses the structure of proteins and their types. 

The denaturation of proteins takes place when the structure of secondary or tertiary proteins get altered due to change of pH or temperature. In the second half of the chapter, you will study how vitamins suffice our daily nutrition intake. 

The last topic of this chapter talks about nucleic acids that are characterized by the presence of a base, a pentose sugar and phosphate moiety. Nucleic acids can be categorized into two types- DNA and RNA. Study the similarities and differences between both of them. 

List of Topics in Chapter 14 “Biomolecules”

  1. Carbohydrates
    1. Classification of Carbohydrates
    2. Monosaccharides
    3. Preparation of Glucose
    4. Structure of Glucose
    5. Cyclic Structure of Glucose
  2. Proteins
    1. Amino Acids
    2. Classification of Amino Acids
    3. Structure of Proteins
    4. Denaturation of Proteins
  3. Enzymes
    1. Mechanism of Enzyme Action
  4. Vitamins
    1. Classification of Vitamins 
  5. Nucleic Acids
    1. Chemical Composition of Nucleic Acids
    2. Structure of Nucleic Acids
    3. Biological Functions of Nucleic Acids
  6. Hormones

Chapter 15: Polymers

At the beginning of this chapter, you will come across a few basic terminologies of this chapter, such as monomer, polymer, and polymerisation. Moving forward, you will understand the importance and types of polymerisation process. 

The preparation of some important synthetic polymers and their properties have also been discussed in this chapter. The names of some commercially important polymers are polypropene, polystyrene, PVC, and bakelite. Biodegradable polymers have found its extensive use as it is eco-friendly and safeguard us from potential environmental hazards. 

List of Topics in Chapter 15 “Polymers”

  1. Classification of Polymers
  2. Types of Polymerisation Reactions
    1. Addition Polymerisation or Chain Growth Polymerisation
    2. Mechanism of Addition Polymerisation
  3. Molecular Mass of Polymers
  4. Biodegradable Polymers
  5. Polymers of Commercial Importance