CBSE Class 12 Chemistry Revision Notes

CBSE Class 12 Chemistry Revision Notes cover the formulas, reactions, mechanisms and concepts included in the current 10-unit syllabus. They help students revise Physical, Inorganic and Organic Chemistry in a clear chapter-wise format.

Class 12 Chemistry connects numerical concepts with chemical reactions, bonding, periodic trends and molecular structures. The current syllabus contains three Physical Chemistry units, two Inorganic Chemistry units and five units covering Organic Chemistry and biomolecules.

These CBSE Class 12 Chemistry Revision Notes follow the 2026–27 unit sequence. Use them to recall formulas, reaction conditions, chemical properties and important concepts before examinations.

Key Takeaways

• 10 units: The current theory syllabus contains Unit I to Unit X.
• 70 marks: The written Chemistry examination carries 70 marks.
• 9 marks: Electrochemistry has the highest individual unit weightage.
• Three areas: The syllabus covers Physical, Inorganic and Organic Chemistry.

Access Class 12 Chemistry Notes in 30 Minutes

Revise the syllabus in three parts:

• First 10 minutes: Units I to III, including Solutions, Electrochemistry and Chemical Kinetics
• Next 10 minutes: Units IV and V, including d- and f-Block Elements and Coordination Compounds
• Final 10 minutes: Units VI to X, including organic reactions, amines and biomolecules

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Chapter-Wise CBSE Class 12 Chemistry Notes

Physical Chemistry Notes Class 12

Physical Chemistry includes Units I to III. These units require formula recall, correct units and regular numerical practice.

Unit I: Solutions

A solution is a homogeneous mixture of two or more substances. Important concentration terms include mole fraction, molarity and molality.

Henry’s law is:

p = KHx

For an ideal solution, each volatile component follows Raoult’s law:

pA = pA°xA

The main colligative properties are:

• Relative lowering of vapour pressure
• Elevation of boiling point
• Depression of freezing point
• Osmotic pressure

Osmotic pressure is:

π = CRT

The van’t Hoff factor explains abnormal molar masses caused by association or dissociation of solute particles.

Unit II: Electrochemistry

Electrochemistry studies the conversion of chemical energy into electrical energy and electrical energy into chemical energy.

Oxidation occurs at the anode. Reduction occurs at the cathode.

Cell potential is:

Ecell = Ecathode − Eanode

The Nernst equation at 298 K is:

Ecell = E°cell − 0.0591/n log Q

The relation between Gibbs energy and cell potential is:

ΔG = −nFEcell

Conductivity decreases on dilution because the number of ions per unit volume decreases. Molar conductivity generally increases because ionic mobility improves.

Faraday’s first law is:

w = ZIt

The unit also covers batteries, fuel cells, electrolysis and corrosion.

Unit III: Chemical Kinetics

Chemical kinetics studies reaction rate and the factors affecting it.

The rate law is:

Rate = k[A]m[B]n

The overall order of the reaction is m + n.

For a zero-order reaction:

[R] = [R]0 − kt

For a first-order reaction:

k = 2.303/t log [R]0/[R]

The half-life of a first-order reaction is:

t½ = 0.693/k

The Arrhenius equation connects the rate constant with temperature:

k = Ae−Ea/RT

Inorganic Chemistry Class 12 Short Notes

Inorganic Chemistry includes Units IV and V. Students should revise electronic configurations, oxidation states, colours, magnetic properties and nomenclature.

Unit IV: The d- and f-Block Elements

Transition elements have incompletely filled d-orbitals in their atoms or common oxidation states.

Their important properties include:

• Variable oxidation states
• Coloured ions
• Paramagnetism
• Catalytic activity
• Alloy formation
• Interstitial compound formation

The magnetic moment is:

μ = √n(n + 2) BM

Lanthanoid contraction is the gradual decrease in atomic and ionic size across the lanthanoid series.

The unit also covers potassium dichromate, potassium permanganate, lanthanoids and actinoids.

Unit V: Coordination Compounds

A coordination compound contains a central metal atom or ion bonded to ligands.

Important terms include:

• Ligand
• Coordination number
• Coordination entity
• Oxidation number
• Coordination sphere

Students study IUPAC nomenclature, Werner’s theory, valence bond theory and crystal field theory.

Coordination compounds may show structural isomerism and stereoisomerism. They are important in biological systems, qualitative analysis and metal extraction.

Organic Chemistry Notes Class 12

Organic Chemistry includes Units VI to IX. Revision should focus on reagents, products, mechanisms and reaction conditions.

Unit VI: Haloalkanes and Haloarenes

Haloalkanes contain a halogen bonded to an alkyl group. Haloarenes contain a halogen bonded directly to an aromatic ring.

Important topics include:

• Nature of the C–X bond
• Nucleophilic substitution
• SN1 and SN2 mechanisms
• Elimination reactions
• Optical activity
• Environmental effects of selected compounds

Unit VII: Alcohols, Phenols and Ethers

Alcohols contain an –OH group attached to a saturated carbon. Phenols contain –OH directly attached to an aromatic ring.

Phenol is more acidic than alcohol because the phenoxide ion is stabilised through resonance.

Important reactions include dehydration, oxidation and electrophilic substitution. Ethers undergo cleavage with concentrated hydrogen halides.

Unit VIII: Aldehydes, Ketones and Carboxylic Acids

Aldehydes and ketones contain the carbonyl group. They mainly undergo nucleophilic addition reactions.

Aldehydes generally oxidise more easily than ketones.

Important concepts include:

• Preparation of carbonyl compounds
• Aldol condensation
• Cannizzaro reaction
• Oxidation and reduction
• Acidity of carboxylic acids

Unit IX: Amines

Amines are derivatives of ammonia. They may be primary, secondary or tertiary.

Their basicity depends on structure, electron availability and solvent effects.

Important reactions include:

• Alkylation
• Acylation
• Carbylamine reaction
• Diazotisation
• Coupling reactions

Diazonium salts are important intermediates in the preparation of aromatic compounds and azo dyes.

Unit X: Biomolecules

Biomolecules include carbohydrates, proteins, vitamins and nucleic acids.

Carbohydrates may be monosaccharides, oligosaccharides or polysaccharides.

Proteins contain amino acids joined through peptide bonds. Their structure may be primary, secondary, tertiary or quaternary.

DNA and RNA are nucleic acids. DNA mainly stores genetic information, while RNA performs several roles in protein synthesis.

CBSE Class 12 Chemistry Unit-Wise Marks Distribution