Class 12 Chemistry India

# Class 12 Chemistry India: A Comprehensive Guide

**An in-depth exploration of the CBSE Class 12 Chemistry syllabus, covering key concepts, exam preparation strategies, and essential resources for success.**

—

## Introduction

Welcome to the comprehensive guide to Class 12 Chemistry in India. This course is designed to provide a thorough understanding of the fundamental principles of chemistry, preparing students for the CBSE board examinations and competitive entrance exams like JEE and NEET. We will delve into the core topics, explore their real-world applications, and provide you with the tools and resources you need to excel.

## Course Structure and Syllabus

The Class 12 Chemistry syllabus is divided into 10 key units, each focusing on a specific area of chemistry. Here is a breakdown of the course structure and the marks allocated to each unit:

| Unit | Title | Marks |
|—|—|—|
| 1 | Solutions | 7 |
| 2 | Electrochemistry | 9 |
| 3 | Chemical Kinetics | 7 |
| 4 | d -and f -Block Elements | 7 |
| 5 | Coordination Compounds | 7 |
| 6 | Haloalkanes and Haloarenes | 6 |
| 7 | Alcohols, Phenols and Ethers | 6 |
| 8 | Aldehydes, Ketones and Carboxylic Acids | 8 |
| 9 | Amines | 6 |
| 10 | Biomolecules | 7 |
| **Total** | | **70** |

Now, let’s explore each of these units in detail.

### Unit 1: Solutions

This unit introduces the concepts of solutions and their properties. We will cover topics such as:

* Types of solutions
* Expressing the concentration of solutions
* Solubility of gases in liquids
* Solid solutions
* Colligative properties
* Abnormal molecular mass

### Unit 2: Electrochemistry

Electrochemistry deals with the relationship between electrical energy and chemical changes. Key topics include:

* Redox reactions
* Electrochemical cells
* Nernst equation
* Conductance of electrolytic solutions
* Electrolysis and laws of electrolysis
* Batteries and fuel cells
* Corrosion

### Unit 3: Chemical Kinetics

Chemical kinetics is the study of reaction rates and the factors that affect them. We will explore:

* Rate of a chemical reaction
* Factors influencing the rate of a reaction
* Integrated rate equations
* Collision theory of chemical reactions
* Activation energy

### Unit 4: d -and f -Block Elements

This unit focuses on the properties and trends of the d- and f-block elements in the periodic table. Topics include:

* Position in the periodic table
* Electronic configuration and general properties
* Lanthanoids and actinoids

### Unit 5: Coordination Compounds

Coordination compounds are a fascinating class of compounds with unique bonding and properties. We will cover:

* Werner’s theory of coordination compounds
* Nomenclature of coordination compounds
* Isomerism in coordination compounds
* Bonding in coordination compounds
* Importance and applications of coordination compounds

### Unit 6: Haloalkanes and Haloarenes

This unit introduces the chemistry of halogen-containing organic compounds. Key topics include:

* Classification and nomenclature
* Methods of preparation
* Physical and chemical properties
* Reactions of haloalkanes and haloarenes

### Unit 7: Alcohols, Phenols and Ethers

We will explore the properties and reactions of alcohols, phenols, and ethers. Topics include:

* Classification and nomenclature
* Methods of preparation
* Physical and chemical properties
* Uses of alcohols, phenols, and ethers

### Unit 8: Aldehydes, Ketones and Carboxylic Acids

This unit covers the chemistry of organic compounds containing the carbonyl group. Key topics include:

* Nomenclature and structure of the carbonyl group
* Preparation of aldehydes and ketones
* Physical and chemical properties
* Uses of aldehydes and ketones
* Carboxylic acids: nomenclature, preparation, properties, and uses

### Unit 9: Amines

Amines are organic compounds derived from ammonia. We will study:

* Structure, classification, and nomenclature
* Methods of preparation
* Physical and chemical properties
* Diazonium salts: preparation, chemical reactions, and importance in synthetic organic chemistry

### Unit 10: Biomolecules

This unit explores the chemistry of life, focusing on the molecules that make up living organisms. Topics include:

* Carbohydrates
* Proteins
* Enzymes
* Vitamins
* Nucleic acids

## Embedded YouTube Videos

To enhance your learning experience, we will embed relevant YouTube videos from trusted sources throughout the course content. These videos will provide visual explanations and demonstrations of key concepts.

## Authoritative Citations and References

All information presented in this course is based on authoritative sources, including the NCERT textbook, publications from the CBSE, and other reputable educational resources. We will provide inline citations and a comprehensive list of references at the end of the course.

## Conclusion

This comprehensive guide to Class 12 Chemistry in India will provide you with a solid foundation in the subject and prepare you for success in your examinations. By focusing on a deep understanding of the concepts and their applications, you will be well-equipped to tackle any challenge that comes your way.

## References

[1] National Council of Educational Research and Training. (2023). *Chemistry Part I & II, Class XII*. New Delhi: NCERT.

[2] Central Board of Secondary Education. (2023). *Senior School Curriculum 2025-26, Volume 1*. New Delhi: CBSE.

[3] Khan Academy. (n.d.). *NCERT Chemistry Class 12*. Retrieved from https://www.khanacademy.org/science/class-12-chemistry-india

[4] Vedantu. (n.d.). *Class 12 Chemistry Index*. Retrieved from https://www.vedantu.com/chemistry/class-12-chemistry-index

[5] BYJU’S. (n.d.). *CBSE Class 12 Chemistry Notes*. Retrieved from https://byjus.com/cbse-notes/chemistry-notes-class-12/

[6] Kendriya Vidyalaya Sangathan. (n.d.). *Chemistry Study Material Class XII*. Retrieved from https://robangalore.kvs.gov.in/en/document/chemistry-study-material-class-xii/

## Unit 1: Solutions – A Deeper Dive

Solutions are homogeneous mixtures of two or more components. The component that is present in the largest quantity is known as the **solvent**, and the other components are called **solutes**. In this unit, we will explore the various types of solutions, the different ways to express their concentrations, the factors affecting solubility, and the colligative properties of solutions. [1]

### Types of Solutions

Solutions can be classified based on the physical state of the solute and solvent. The following table summarizes the different types of solutions:

| Type of Solution | Solute | Solvent | Examples |
|—|—|—|—|
| Gaseous Solutions | Gas | Gas | Mixture of oxygen and nitrogen gases |
| | Liquid | Gas | Chloroform mixed with nitrogen gas |
| | Solid | Gas | Camphor in nitrogen gas |
| Liquid Solutions | Gas | Liquid | Oxygen dissolved in water |
| | Liquid | Liquid | Ethanol dissolved in water |
| | Solid | Liquid | Glucose dissolved in water |
| Solid Solutions | Gas | Solid | Solution of hydrogen in palladium |
| | Liquid | Solid | Amalgam of mercury with sodium |
| | Solid | Solid | Copper dissolved in gold (alloys) |

### Expressing Concentration of Solutions

The concentration of a solution can be expressed in several ways. The choice of the method depends on the purpose of the application. The most common methods are:

* **Mass Percentage (w/w):** It is the mass of the solute in grams present in 100 grams of the solution.
* **Volume Percentage (v/v):** It is the volume of the solute in mL present in 100 mL of the solution.
* **Mass by Volume Percentage (w/v):** It is the mass of the solute in grams present in 100 mL of the solution.
* **Parts Per Million (ppm):** This unit is used when a solute is present in trace quantities. It is the number of parts of the solute per million parts of the solution.
* **Mole Fraction (x):** It is the ratio of the number of moles of a particular component to the total number of moles of the solution.
* **Molarity (M):** It is the number of moles of solute dissolved in one liter of the solution.
* **Molality (m):** It is the number of moles of solute per kilogram of the solvent.

### Solubility

Solubility is the maximum amount of a substance that can be dissolved in a specified amount of solvent at a specified temperature. The solubility of a substance depends on the nature of the solute and solvent, temperature, and pressure.

#### Solubility of a Solid in a Liquid

The solubility of a solid in a liquid is affected by temperature and pressure. The effect of temperature depends on the enthalpy of the solution. If the dissolution process is endothermic, the solubility increases with an increase in temperature, and if it is exothermic, the solubility decreases with an increase in temperature. Pressure does not have any significant effect on the solubility of solids in liquids as these are highly incompressible.

#### Solubility of a Gas in a Liquid

The solubility of a gas in a liquid is governed by **Henry’s Law**, which states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas present above the surface of the liquid or solution. The law is expressed as:

> p = K_H * x

where ‘p’ is the partial pressure of the gas, ‘x’ is the mole fraction of the gas in the solution, and K_H is the Henry’s law constant.

### Raoult’s Law and Colligative Properties

**Raoult’s Law** states that for a solution of volatile liquids, the partial vapor pressure of each component in the solution is directly proportional to its mole fraction. [1]

Colligative properties are the properties of solutions that depend on the ratio of the number of solute particles to the number of solvent molecules in a solution, and not on the nature of the chemical species present. There are four main colligative properties:

1. **Relative Lowering of Vapor Pressure:** The vapor pressure of a solvent over a solution is less than that of the pure solvent. The relative lowering of vapor pressure is equal to the mole fraction of the solute.
2. **Elevation of Boiling Point:** The boiling point of a solution is always higher than that of the pure solvent. The elevation of the boiling point is directly proportional to the molal concentration of the solute.
3. **Depression of Freezing Point:** The freezing point of a solution is always lower than that of the pure solvent. The depression of the freezing point is directly proportional to the molal concentration of the solute.
4. **Osmotic Pressure:** Osmosis is the spontaneous movement of solvent molecules through a semi-permeable membrane from a region of higher solvent concentration to a region of lower solvent concentration. Osmotic pressure is the pressure that must be applied to a solution to prevent the inward flow of its pure solvent across a semi-permeable membrane.

### Abnormal Molar Mass

When the molar mass of a substance determined by studying any of the colligative properties comes out to be different than the theoretically expected value, it is called abnormal molar mass. This is usually due to the association or dissociation of solute molecules in the solution. The **van’t Hoff factor (i)** is used to account for the extent of association or dissociation.

> i = (Normal molar mass) / (Abnormal molar mass)

### Embedded Video: Solutions Class 12

To further clarify these concepts, here is a helpful video from Vedantu JEE Made Ejee:

>

-share” allowfullscreen>

This video provides a comprehensive overview of the topics covered in this unit.

## Unit 2: Electrochemistry – The Science of Electrical and Chemical Energy

Electrochemistry is a branch of chemistry that studies the relationship between electrical energy and chemical reactions. It explores how chemical reactions can generate electricity and how electrical energy can be used to drive non-spontaneous chemical reactions. This field is crucial for understanding a wide range of applications, from batteries and fuel cells to corrosion and industrial electrolysis. [1]

### Electrochemical Cells

An electrochemical cell is a device that can generate electrical energy from a chemical reaction or use electrical energy to cause a chemical reaction. There are two types of electrochemical cells:

* **Galvanic Cells (or Voltaic Cells):** These cells convert the chemical energy of a spontaneous redox reaction into electrical energy. A common example is the Daniell cell.
* **Electrolytic Cells:** These cells use electrical energy to drive a non-spontaneous redox reaction. Electrolysis is the process that occurs in an electrolytic cell.

### Standard Electrode Potential

The **standard electrode potential (E°)** of an electrode is the potential difference between the electrode and the electrolyte under standard conditions (1 M concentration, 1 atm pressure for gases, and 298 K). The standard hydrogen electrode (SHE) is used as a reference electrode, and its standard electrode potential is defined as zero.

### Nernst Equation

The Nernst equation relates the electrode potential of an electrochemical cell to the concentrations of the reactants and products. For a general electrochemical reaction:

> aA + bB → cC + dD

The Nernst equation is given by:

> E_cell = E°_cell – (RT/nF) * ln(Q)

where:
* E_cell is the cell potential under non-standard conditions.
* E°_cell is the standard cell potential.
* R is the ideal gas constant.
* T is the temperature in Kelvin.
* n is the number of moles of electrons transferred in the reaction.
* F is the Faraday constant.
* Q is the reaction quotient.

### Conductance of Electrolytic Solutions

The conductance of an electrolytic solution is a measure of its ability to conduct electricity. It is the reciprocal of resistance (R). The conductivity (κ) of a solution is the conductance of a solution of 1 cm length with a cross-sectional area of 1 cm². Molar conductivity (Λ_m) is the conductivity of a solution containing one mole of electrolyte.

**Kohlrausch’s Law** states that the limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte.

### Electrolysis and Laws of Electrolysis

Electrolysis is the process of using electricity to bring about a non-spontaneous chemical reaction. **Faraday’s laws of electrolysis** govern the quantitative aspects of electrolysis:

* **First Law:** The amount of chemical reaction which occurs at any electrode during electrolysis by a current is proportional to the quantity of electricity passed through the electrolyte.
* **Second Law:** The amounts of different substances liberated by the same quantity of electricity passing through the electrolytic solution are proportional to their chemical equivalent weights.

### Batteries, Fuel Cells, and Corrosion

* **Batteries:** Batteries are galvanic cells that are used as a source of electrical energy. They can be primary (non-rechargeable) or secondary (rechargeable).
* **Fuel Cells:** Fuel cells are galvanic cells that are designed to convert the energy of combustion of fuels like hydrogen, methane, etc., directly into electrical energy.
* **Corrosion:** Corrosion is the gradual destruction of metals by chemical or electrochemical reaction with their environment. The rusting of iron is a common example of corrosion.

### Embedded Video: Electrochemistry Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 3: Chemical Kinetics – The Study of Reaction Rates

Chemical kinetics is the branch of chemistry that deals with the rate of chemical reactions, the factors that influence these rates, and the mechanisms by which reactions occur. Understanding chemical kinetics is essential for controlling reaction speeds, optimizing industrial processes, and gaining insights into the fundamental steps of a reaction. [1]

### Rate of a Chemical Reaction

The rate of a chemical reaction can be defined as the change in concentration of a reactant or product in unit time. The rate can be expressed as:

* **Average Rate:** The rate of reaction over a specific time interval.
* **Instantaneous Rate:** The rate of reaction at a particular instant in time.

### Factors Influencing the Rate of a Reaction

Several factors can affect the rate of a chemical reaction:

* **Concentration of Reactants:** The rate of a reaction generally increases with an increase in the concentration of reactants.
* **Temperature:** The rate of a reaction usually increases with an increase in temperature. A general rule of thumb is that for many reactions, the rate doubles for every 10°C rise in temperature.
* **Presence of a Catalyst:** A catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
* **Surface Area of Reactants:** For reactions involving solids, the rate of reaction increases with an increase in the surface area of the reactant.
* **Presence of Light:** Some reactions, known as photochemical reactions, are influenced by the presence of light.

### Integrated Rate Equations and Half-Life

An integrated rate equation is a mathematical expression that relates the concentration of a reactant to time. The half-life (t_1/2) of a reaction is the time required for the concentration of a reactant to be reduced to one-half of its initial concentration.

* **Zero-Order Reactions:** The rate of the reaction is independent of the concentration of the reactant. The half-life is directly proportional to the initial concentration.
* **First-Order Reactions:** The rate of the reaction is directly proportional to the concentration of the reactant. The half-life is independent of the initial concentration.

### Collision Theory of Chemical Reactions

The collision theory states that for a chemical reaction to occur, the reacting molecules must collide with each other with sufficient energy and in the proper orientation. The minimum energy required for a collision to be effective is called the **activation energy (E_a)**.

### Arrhenius Equation

The Arrhenius equation gives the relationship between the rate constant (k) of a reaction and the temperature (T):

> k = A * e^-Ea/RT

where:
* k is the rate constant.
* A is the pre-exponential factor or frequency factor.
* E_a is the activation energy.
* R is the ideal gas constant.
* T is the temperature in Kelvin.

### Embedded Video: Chemical Kinetics Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 4: d -and f -Block Elements – The Transition and Inner Transition Metals

The d-block elements, also known as transition metals, and the f-block elements, or inner transition metals, are a fascinating and important group of elements in the periodic table. They exhibit a wide range of chemical and physical properties that make them essential in various industrial, biological, and technological applications. [1]

### Position in the Periodic Table and Electronic Configuration

The d-block elements are located in groups 3-12 of the periodic table, between the s-block and p-block elements. They are characterized by the filling of the d-orbitals of the penultimate energy level. The f-block elements are located at the bottom of the periodic table and are characterized by the filling of the f-orbitals of the ante-penultimate energy level. The f-block consists of two series: the lanthanoids and the actinoids.

### General Properties of the Transition Elements (d-Block)

The transition elements exhibit several characteristic properties:

* **Metallic Character:** All transition elements are metals with high tensile strength, ductility, malleability, and thermal and electrical conductivity.
* **Variable Oxidation States:** Transition elements show variable oxidation states due to the participation of both ns and (n-1)d electrons in bonding.
* **Formation of Colored Ions:** Most of the compounds of transition metals are colored in the solid or solution state. This is due to the presence of unpaired electrons and d-d transitions.
* **Magnetic Properties:** Many transition metals and their compounds are paramagnetic due to the presence of unpaired electrons.
* **Catalytic Properties:** Transition metals and their compounds are known for their catalytic activity. This is attributed to their ability to adopt multiple oxidation states and to form complexes.
* **Formation of Complex Compounds:** Transition metals have a strong tendency to form complex compounds with various ligands.
* **Formation of Interstitial Compounds:** Transition metals can trap small atoms like hydrogen, carbon, and nitrogen in the interstitial sites of their crystal lattices to form interstitial compounds.
* **Alloy Formation:** Transition metals form a large number of alloys.

### The Lanthanoids and Actinoids (f-Block)

* **Lanthanoids:** The 14 elements following lanthanum (La) are called lanthanoids. They have the general electronic configuration [Xe] 4f^1-14 5d^0-1 6s². The most common oxidation state of lanthanoids is +3. **Lanthanoid contraction** is the steady decrease in the atomic and ionic radii of the lanthanoids with an increase in atomic number.
* **Actinoids:** The 14 elements following actinium (Ac) are called actinoids. They have the general electronic configuration [Rn] 5f^1-14 6d^0-1 7s². The actinoids exhibit a wider range of oxidation states than the lanthanoids. They are all radioactive.

### Embedded Video: d -and f -Block Elements Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 5: Coordination Compounds – The Chemistry of Complexes

Coordination compounds, also known as complex compounds, are a unique and important class of compounds in which a central metal atom or ion is bonded to a group of surrounding molecules or ions, known as ligands. These compounds play a vital role in various chemical and biological systems, from industrial catalysis to the transport of oxygen in our blood. [1]

### Werner’s Theory of Coordination Compounds

Alfred Werner, the father of coordination chemistry, was the first to propose a successful theory to explain the properties of coordination compounds. The main postulates of Werner’s theory are:

* In coordination compounds, metals show two types of linkages (valences) – primary and secondary.
* The primary valences are ionizable and are satisfied by negative ions.
* The secondary valences are non-ionizable and are satisfied by neutral molecules or negative ions. The secondary valence is equal to the coordination number and is fixed for a metal.
* The ions/groups bound by the secondary linkages to the metal have characteristic spatial arrangements corresponding to different coordination numbers.

### Nomenclature of Coordination Compounds

The International Union of Pure and Applied Chemistry (IUPAC) has established a set of rules for the systematic naming of coordination compounds. The key rules include:

* The cation is named first, followed by the anion.
* Ligands are named in alphabetical order before the name of the central metal atom/ion.
* The names of anionic ligands end in -o, those of neutral and cationic ligands are the same, except for a few special cases.
* Prefixes mono-, di-, tri-, etc., are used to indicate the number of individual ligands in the coordination entity.
* The oxidation state of the central metal atom/ion is indicated by a Roman numeral in parenthesis.
* If the complex ion is an anion, the name of the central metal atom ends with the suffix -ate.

### Isomerism in Coordination Compounds

Isomerism is the phenomenon in which two or more compounds have the same chemical formula but different arrangements of atoms. Coordination compounds exhibit two main types of isomerism:

* **Stereoisomerism:** This type of isomerism arises due to different spatial arrangements of ligands around the central metal atom. It is further divided into:
* **Geometrical Isomerism:** This arises in heteroleptic complexes due to different possible geometric arrangements of the ligands.
* **Optical Isomerism:** This arises when a coordination compound and its mirror image are non-superimposable.
* **Structural Isomerism:** This type of isomerism arises due to the difference in the structure of the coordination compound. It is further divided into:
* **Linkage Isomerism:** This arises in a coordination compound containing an ambidentate ligand.
* **Coordination Isomerism:** This arises from the interchange of ligands between cationic and anionic entities of different metal ions present in a complex.
* **Ionization Isomerism:** This arises when the counter ion in a complex salt is itself a potential ligand and can displace a ligand which can then become the counter ion.
* **Solvate Isomerism:** This is also known as hydrate isomerism. In this, water is taken as the solvent.

### Bonding in Coordination Compounds

Several theories have been proposed to explain the nature of bonding in coordination compounds. The most important ones are:

* **Valence Bond Theory (VBT):** This theory explains the formation of complexes in terms of coordinate covalent bonds. It accounts for the structure and magnetic properties of a large number of coordination compounds.
* **Crystal Field Theory (CFT):** This theory is an electrostatic model which considers the metal-ligand bond to be ionic, arising purely from electrostatic interaction between the metal ion and the ligand.

### Importance and Applications of Coordination Compounds

Coordination compounds are of great importance in various fields:

* **In Analytical Chemistry:** Coordination compounds are used in the qualitative and quantitative analysis of metal ions.
* **In Metallurgy:** They are used in the extraction of metals like gold and silver.
* **In Biological Systems:** Many biologically important compounds are coordination compounds, such as hemoglobin, chlorophyll, and vitamin B12.
* **In Medicine:** Coordination compounds are used in the treatment of various diseases. For example, cisplatin is used in the treatment of cancer.
* **In Industry:** They are used as catalysts in many industrial processes.

### Embedded Video: Coordination Compounds Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 6: Haloalkanes and Haloarenes – The World of Halogenated Organic Compounds

Haloalkanes and haloarenes are a class of organic compounds that are formed by the replacement of one or more hydrogen atoms in an aliphatic or aromatic hydrocarbon, respectively, with a halogen atom (fluorine, chlorine, bromine, or iodine). These compounds have a wide range of applications, from solvents and refrigerants to pharmaceuticals and pesticides. [1]

### Classification and Nomenclature

Haloalkanes and haloarenes can be classified based on the number of halogen atoms and the nature of the carbon atom to which the halogen is attached. The IUPAC system of nomenclature is used for naming these compounds.

### Methods of Preparation

Haloalkanes and haloarenes can be prepared by various methods:

* **From Alcohols:** Haloalkanes can be prepared from alcohols by reacting them with hydrogen halides, phosphorus halides, or thionyl chloride.
* **From Hydrocarbons:** Haloalkanes can be prepared from hydrocarbons by free radical halogenation. Haloarenes can be prepared from aromatic hydrocarbons by electrophilic substitution.
* **From Alkenes and Alkynes:** Haloalkanes can be prepared from alkenes and alkynes by the addition of hydrogen halides.
* **From Diazonium Salts:** Haloarenes can be prepared from diazonium salts by the Sandmeyer reaction or the Gattermann reaction.

### Physical and Chemical Properties

The physical and chemical properties of haloalkanes and haloarenes are determined by the nature of the carbon-halogen bond. The C-X bond is polar, with the carbon atom having a partial positive charge and the halogen atom having a partial negative charge.

* **Physical Properties:** Haloalkanes are generally colorless, sweet-smelling liquids. The boiling points of haloalkanes are higher than those of the corresponding alkanes. The boiling points increase with an increase in the size of the halogen atom.
* **Chemical Properties:** Haloalkanes and haloarenes undergo a variety of chemical reactions, including:
* **Nucleophilic Substitution Reactions:** These are the most common reactions of haloalkanes. The halogen atom is replaced by a nucleophile.
* **Elimination Reactions:** Haloalkanes can undergo elimination reactions to form alkenes.
* **Reaction with Metals:** Haloalkanes react with metals to form organometallic compounds, such as Grignard reagents.
* **Electrophilic Substitution Reactions:** Haloarenes undergo electrophilic substitution reactions, such as halogenation, nitration, and sulfonation.

### Embedded Video: Haloalkanes and Haloarenes Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 7: Alcohols, Phenols and Ethers – The Oxygen-Containing Organic Compounds

Alcohols, phenols, and ethers are classes of organic compounds that contain a carbon-oxygen single bond. These compounds are widespread in nature and have numerous applications in industry, medicine, and daily life. [1]

### Classification and Nomenclature

* **Alcohols:** Alcohols are compounds in which a hydroxyl (-OH) group is attached to a saturated carbon atom. They are classified as primary, secondary, or tertiary, depending on the number of carbon atoms attached to the carbon atom bearing the -OH group.
* **Phenols:** Phenols are compounds in which a hydroxyl group is directly attached to an aromatic ring.
* **Ethers:** Ethers are compounds in which an oxygen atom is bonded to two alkyl or aryl groups.

The IUPAC system is used for naming these compounds.

### Methods of Preparation

Alcohols, phenols, and ethers can be prepared by various methods:

* **Alcohols:** They can be prepared from alkenes (by hydration), from carbonyl compounds (by reduction), and from Grignard reagents.
* **Phenols:** They can be prepared from haloarenes, from diazonium salts, and from cumene.
* **Ethers:** They can be prepared by the dehydration of alcohols and by the Williamson synthesis.

### Physical and Chemical Properties

The physical and chemical properties of alcohols, phenols, and ethers are influenced by the presence of the C-O bond and, in the case of alcohols and phenols, the -OH group.

* **Physical Properties:** The boiling points of alcohols and phenols are higher than those of other classes of compounds of comparable molecular mass due to the presence of intermolecular hydrogen bonding. The solubility of alcohols and phenols in water is due to their ability to form hydrogen bonds with water molecules.
* **Chemical Properties:**
* **Alcohols:** They undergo reactions involving the cleavage of the O-H bond and the C-O bond. They can act as nucleophiles and electrophiles.
* **Phenols:** The -OH group in phenols is acidic in nature. Phenols undergo electrophilic substitution reactions.
* **Ethers:** Ethers are relatively inert compounds. The C-O bond in ethers can be cleaved by hydrogen halides.

### Uses of Alcohols, Phenols, and Ethers

* **Alcohols:** Ethanol is used as a solvent, a beverage, and a fuel. Methanol is used as a solvent and as a raw material for the production of other chemicals.
* **Phenols:** Phenol is used as an antiseptic and as a raw material for the production of polymers like Bakelite.
* **Ethers:** Diethyl ether is used as a solvent and as an anesthetic.

### Embedded Video: Alcohols, Phenols and Ethers Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 8: Aldehydes, Ketones and Carboxylic Acids – The Carbonyl Compounds

Aldehydes, ketones, and carboxylic acids are classes of organic compounds that contain the carbonyl group (C=O). These compounds are of great importance in both industry and biological systems. They are found in fragrances, flavors, and hormones, and are used in the synthesis of many other organic compounds. [1]

### Nomenclature and Structure of the Carbonyl Group

The carbonyl group consists of a carbon atom double-bonded to an oxygen atom. The carbon atom of the carbonyl group is sp²-hybridized and forms three sigma (σ) bonds. The fourth valence electron of carbon remains in its p-orbital and forms a pi (π) bond with oxygen. The C=O bond is polar, with the oxygen atom being more electronegative than the carbon atom.

### Preparation of Aldehydes and Ketones

Aldehydes and ketones can be prepared by several methods:

* **By Oxidation of Alcohols:** Primary alcohols are oxidized to aldehydes, and secondary alcohols are oxidized to ketones.
* **By Dehydrogenation of Alcohols:** Aldehydes and ketones can be prepared by the catalytic dehydrogenation of primary and secondary alcohols, respectively.
* **From Hydrocarbons:** Aldehydes and ketones can be prepared from hydrocarbons by ozonolysis of alkenes and by hydration of alkynes.
* **From Acyl Chlorides (Acid Chlorides):** Aldehydes can be prepared from acyl chlorides by catalytic hydrogenation (Rosenmund reduction). Ketones can be prepared from acyl chlorides by reacting them with dialkylcadmium.
* **From Nitriles and Esters:** Aldehydes and ketones can be prepared from nitriles and esters by reduction.

### Physical and Chemical Properties

* **Physical Properties:** The boiling points of aldehydes and ketones are higher than those of nonpolar compounds of comparable molecular mass. The lower members of aldehydes and ketones are soluble in water.
* **Chemical Properties:** Aldehydes and ketones undergo a variety of chemical reactions, including:
* **Nucleophilic Addition Reactions:** The carbonyl group is susceptible to nucleophilic attack. Aldehydes are generally more reactive than ketones towards nucleophilic addition reactions.
* **Reduction:** Aldehydes and ketones can be reduced to primary and secondary alcohols, respectively.
* **Oxidation:** Aldehydes are easily oxidized to carboxylic acids. Ketones are generally resistant to oxidation.
* **Reactions due to α-Hydrogen:** The α-hydrogen atoms of aldehydes and ketones are acidic in nature. This leads to several important reactions, such as the aldol condensation and the Cannizzaro reaction.

### Carboxylic Acids

Carboxylic acids are organic compounds that contain the carboxyl group (-COOH). They are acidic in nature and have a wide range of applications.

* **Nomenclature and Structure:** The IUPAC system is used for naming carboxylic acids.
* **Methods of Preparation:** Carboxylic acids can be prepared by the oxidation of primary alcohols and aldehydes, from nitriles and Grignard reagents, and by the hydrolysis of esters.
* **Physical and Chemical Properties:** Carboxylic acids have high boiling points due to the presence of intermolecular hydrogen bonding. They are acidic and react with bases to form salts. They also undergo reactions involving the cleavage of the C-OH bond.

### Embedded Video: Aldehydes, Ketones and Carboxylic Acids Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 9: Amines – The Nitrogen-Containing Organic Compounds

Amines are a class of organic compounds that are derived from ammonia (NH₃) by replacing one or more hydrogen atoms with alkyl or aryl groups. They are of great importance in nature, being found in proteins, vitamins, alkaloids, and hormones. They also have numerous applications in the synthesis of drugs, dyes, and polymers. [1]

### Structure, Classification, and Nomenclature

Amines are classified as primary (1°), secondary (2°), or tertiary (3°), depending on the number of hydrogen atoms of ammonia that have been replaced by alkyl or aryl groups. The IUPAC system is used for naming amines.

### Methods of Preparation

Amines can be prepared by several methods:

* **Reduction of Nitro Compounds:** Nitro compounds can be reduced to amines by passing hydrogen gas in the presence of finely divided nickel, palladium, or platinum, or by reduction with metals in an acidic medium.
* **Ammonolysis of Alkyl Halides:** Alkyl halides react with an ethanolic solution of ammonia to undergo nucleophilic substitution reaction in which the halogen atom is replaced by an amino (-NH₂) group.
* **Reduction of Nitriles:** Nitriles can be reduced to primary amines by lithium aluminium hydride (LiAlH₄) or by catalytic hydrogenation.
* **Reduction of Amides:** Amides can be reduced to amines by LiAlH₄.
* **Gabriel Phthalimide Synthesis:** This method is used for the preparation of primary amines. Phthalimide on treatment with ethanolic potassium hydroxide forms potassium salt of phthalimide which on heating with alkyl halide followed by alkaline hydrolysis produces the corresponding primary amine.
* **Hofmann Bromamide Degradation Reaction:** This method is used for the preparation of primary amines. An amide is treated with bromine in an aqueous or ethanolic solution of sodium hydroxide.

### Physical and Chemical Properties

* **Physical Properties:** The lower aliphatic amines are gases with a fishy odor. Primary and secondary amines are engaged in intermolecular association due to hydrogen bonding between nitrogen of one and hydrogen of another molecule. The boiling points of amines are higher than those of hydrocarbons of comparable molecular mass.
* **Chemical Properties:** Amines are basic in nature due to the presence of a lone pair of electrons on the nitrogen atom. They react with acids to form salts. They also undergo a variety of other reactions, such as alkylation, acylation, and reaction with nitrous acid.

### Diazonium Salts

Diazonium salts have the general formula RN₂⁺X^–, where R stands for an aryl group and X^– is an anion like Cl^–, Br^–, HSO₄^–, etc. They are of great importance in the synthesis of a variety of aromatic compounds.

* **Preparation:** Diazonium salts are prepared by treating an aromatic primary amine with nitrous acid at low temperatures.
* **Chemical Reactions:** The diazonium group can be replaced by a variety of other groups, such as -OH, -F, -Cl, -Br, -I, -CN, and -H. Diazonium salts also undergo coupling reactions to form azo dyes.

### Embedded Video: Amines Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit:

## Unit 10: Biomolecules – The Molecules of Life

Biomolecules are the complex organic molecules that make up living organisms and are essential for their survival. They include carbohydrates, proteins, nucleic acids, lipids, and vitamins. In this unit, we will explore the structure, function, and importance of these vital molecules. [1]

### Carbohydrates

Carbohydrates are a major class of biomolecules that are a primary source of energy for living organisms. They are polyhydroxy aldehydes or ketones or substances that yield these on hydrolysis. Carbohydrates are classified as monosaccharides, disaccharides, and polysaccharides.

* **Monosaccharides:** These are the simplest carbohydrates that cannot be hydrolyzed further to give simpler units of polyhydroxy aldehyde or ketone. Examples include glucose and fructose.
* **Disaccharides:** These are carbohydrates that on hydrolysis give two molecules of either the same or different monosaccharides. Examples include sucrose, lactose, and maltose.
* **Polysaccharides:** These are carbohydrates that on hydrolysis yield a large number of monosaccharide units. Examples include starch, cellulose, and glycogen.

### Proteins

Proteins are the most abundant biomolecules in living systems. They are polymers of α-amino acids. Proteins perform a wide variety of functions in living organisms, including catalyzing metabolic reactions, DNA replication, responding to stimuli, and transporting molecules from one location to another.

* **Amino Acids:** Amino acids are the building blocks of proteins. They contain both an amino group and a carboxyl group.
* **Structure of Proteins:** The structure of proteins can be described at four levels: primary, secondary, tertiary, and quaternary.

### Enzymes

Enzymes are biological catalysts that speed up the rate of biochemical reactions without being consumed in the process. Most enzymes are proteins.

### Vitamins

Vitamins are organic compounds that are required in small amounts in the diet for the normal growth and maintenance of the body. They are classified as fat-soluble (A, D, E, and K) and water-soluble (B and C).

### Nucleic Acids

Nucleic acids are the biomolecules that carry the genetic information in a cell and are responsible for the transmission of traits from one generation to the next. There are two types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

* **Structure of Nucleic Acids:** Nucleic acids are polymers of nucleotides. Each nucleotide consists of a nitrogenous base, a pentose sugar, and a phosphate group.

### Embedded Video: Biomolecules Class 12

This video from Vedantu JEE Made Ejee provides a detailed explanation of the concepts covered in this unit: