NCERT Class 12 Chemistry is a vital subject for students preparing for CBSE board exams and competitive tests like JEE and NEET. This textbook focuses on understanding atomic structure, bonding, reactions, and the properties of matter from both theoretical and practical perspectives. The topics are designed to strengthen students’ conceptual base and enhance their problem-solving skills.
The syllabus is divided into Physical Chemistry, Organic Chemistry, and Inorganic Chemistry. Each unit builds on the knowledge gained in Class 11, helping learners connect basic chemistry with real-world applications in medicine, engineering, and environmental science. Mastery of equations, numerical problems, and conceptual reasoning is key to scoring high marks.
In this detailed guide, you’ll find chapter-wise concepts, important formulas, and summary tables, all structured to simplify understanding and improve retention. Let’s go through the main topics in an organized, exam-oriented manner.
Table of Contents
Solid State
Types of Solids and Their Properties
| Type of Solid | Constituents | Forces of Attraction | Example |
|---|---|---|---|
| Ionic Solid | Cations and Anions | Electrostatic Forces | NaCl, KBr |
| Molecular Solid | Molecules | Van der Waals, Dipole Forces | I2, CO2 |
| Metallic Solid | Positive Ions and Delocalized Electrons | Metallic Bond | Fe, Cu |
| Covalent Solid | Atoms connected via covalent bonds | Strong Covalent Bond | Diamond, SiO2 |
The Solid State chapter focuses on the arrangement of atoms, crystal lattices, and types of solids. Students learn to differentiate between amorphous and crystalline solids and understand how interatomic forces determine melting points, hardness, and conductivity. The study of unit cell parameters like edge length and coordination number strengthens spatial understanding of crystal geometry.
The \(a^3 = ZM / (N_A
ho)\) formula connects density with unit cell structure. Learning these relationships helps in calculating lattice parameters, a frequent topic in exams and entrance tests.
Electrochemistry
Redox Reactions and Cell Potentials
| Concept | Formula | Application |
|---|---|---|
| Nernst Equation | \(E = E^0 – \frac{RT}{nF} \ln Q\) | Calculates electrode potential under non-standard conditions |
| Faraday’s Laws | \(W = ZIt\) | Determines mass deposited during electrolysis |
| Conductance | \(\kappa = \frac{1}{ ho}\) |
Measures ability of an electrolyte to conduct current |
Electrochemistry connects chemistry with electricity. It teaches how redox reactions generate current in cells. The Nernst Equation helps calculate electrode potential, and Faraday’s Laws of Electrolysis relate charge to the amount of substance deposited. Understanding these principles is crucial for predicting the direction of spontaneous reactions.
For example, in a Daniell cell, zinc acts as the anode (oxidation) and copper as the cathode (reduction). Applying \(E_{cell} = E_{cathode} – E_{anode}\) helps determine overall cell voltage, a concept tested often in board and competitive exams.
Organic Compounds
Classification, Nomenclature, and Reactions
| Functional Group | General Formula | Example | Type of Reaction |
|---|---|---|---|
| Alcohol | R–OH | Ethanol | Dehydration, Oxidation |
| Aldehyde | R–CHO | Formaldehyde | Nucleophilic Addition |
| Carboxylic Acid | R–COOH | Acetic Acid | Decarboxylation |
| Amine | R–NH2 | Methylamine | Substitution |
Organic Chemistry explores carbon-containing compounds and their reactions. Students learn systematic naming (IUPAC), isomerism, and reaction mechanisms. Functional groups determine chemical behavior, such as oxidation in alcohols or substitution in halides.
For instance, oxidation of ethanol yields acetaldehyde and then acetic acid: \(CH_3CH_2OH
ightarrow CH_3CHO
ightarrow CH_3COOH\). Understanding these stepwise mechanisms helps in writing reaction equations accurately and predicting products in complex organic transformations.
Coordination Compounds
Structures, Nomenclature, and Bonding
| Complex Ion | Coordination Number | Ligand Type | Example |
|---|---|---|---|
| [Fe(CN)6]4− | 6 | Monodentate | Potassium ferrocyanide |
| [Co(NH3)6]3+ | 6 | Neutral Ligand | Hexaamminecobalt(III) |
| [CuCl4]2− | 4 | Unidentate | Tetrachlorocuprate(II) |
Coordination Compounds involve central metal ions bonded to ligands. They exhibit unique magnetic and optical properties explained by Crystal Field Theory (CFT). For example, in an octahedral complex, the \(d\)-orbitals split into two energy levels, leading to the formula \(Delta_0 = E_{e_g} – E_{t_{2g}}\).
Students should learn how ligand type affects geometry, color, and stability. Complexes like [Fe(CN)_6]^{4-} (low spin) and [Fe(H_2O)_6]^{2+} (high spin) differ due to field strength, a concept central to both board exams and entrance tests.