Chemistry Formulas for Class 11 & 12 – Physical, Organic, Inorganic [PDF]

Chemistry Formulas are the backbone of mastering Class 11 and 12 Chemistry for board exams and competitive entrance tests like JEE and NEET. On this page, Hodu Academy presents a chapter-wise collection of all-important chemistry formulas from Physical, Organic, and Inorganic Chemistry – designed for quick revision, doubt clearance, and scoring top marks.

Use these formula sheets, mind maps, and short notes for Class 11 and 12 Chemistry to understand fundamental concepts, solve numerical problems, memorize key reactions, and tackle MCQs with confidence.
Whether you’re preparing for CBSE, ICSE, or State boards – or aiming for competitive exams – these formula tables are your essential last-minute revision tool!

Class 11 Chemistry Formula List

Class 11 Chemistry is all about fundamentals – Mole concept, Atomic structure, States of matter, Thermodynamics, Chemical bonding, and the basics of Organic and Inorganic chemistry. Below is a chapter-wise table of the most important formulas to remember for Class 11 Chemistry (Physical, Organic & Inorganic):

Chapter Name	Key Formulas & Concepts
Some Basic Concepts of Chemistry	Mole = Mass (g)/Molar mass, % Composition, Avogadro’s Law: 1 mole = 6.022×10²³, Empirical/Molecular formula
Structure of Atom	e/m of electron, Bohr’s model: rₙ = n²h²/4π²mₑZe², Eₙ = -13.6Z²/n² eV
Classification of Elements & Periodicity	Periodic trends, Atomic/ionic radius, Ionization energy, Electron affinity
Chemical Bonding & Molecular Structure	Octet rule, VSEPR theory, Hybridization, Dipole moment μ = q × d
States of Matter	Gas laws (Boyle’s, Charles’), PV=nRT, Kinetic energy = 3/2 RT
Thermodynamics	ΔU = q + w, ΔH = ΔU + PΔV, q = mCΔT, Hess’s law
Equilibrium	Kc, Kp, Le Chatelier’s principle, pH = -log[H⁺]
Redox Reactions	Oxidation number, Balancing equations, Disproportionation
Organic Chemistry - Some Basic Principles	Hybridization, Nomenclature, IUPAC rules, Resonance, Isomerism
Hydrocarbons	General formulas, Alkanes (CnH₂n+₂), Alkenes (CnH₂n), Alkynes (CnH₂n-2), Reactions

Class 11 Chemistry: Chapter-wise Formula List (Expand for Details)

Note: Only chapters with significant formulas are included.

Class 12 Chemistry Formula List

Class 12 Chemistry is the key to scoring high in board and competitive exams. The focus is on advanced chapters: Electrochemistry, Chemical Kinetics, Surface Chemistry, d & f block elements, Organic Chemistry reactions, and Biomolecules. Use this chapter-wise formula table to revise before exams.

Chapter Name	Key Formulas & Concepts
Solutions	Molarity M = moles/L, Molality m = moles/kg, % w/w, Raoult’s Law: P₁ = X₁P₁⁰
Electrochemistry	Faraday’s laws, E°cell = E°cathode - E°anode, Nernst Eqn: E = E° - (0.059/n)logQ
Chemical Kinetics	Rate = Δ[C]/Δt, First order: k = (2.303/t)log(a/a-x), t₁/₂ = 0.693/k
Surface Chemistry	Adsorption, Freundlich isotherm: x/m = kP¹⁄ⁿ, Catalysis
d and f Block Elements	Electronic configuration, Properties, Color, Magnetic behavior
Coordination Compounds	Werner’s theory, Nomenclature, Crystal Field Theory
Aldehydes, Ketones and Carboxylic Acids	Functional group test, Oxidation/reduction, Reaction mechanisms
Amines	Classification, Preparation, Diazotization, Hofmann’s elimination
Biomolecules	Carbohydrates, Proteins, Nucleic acids – Structure, Functions
Polymers	Addition/Condensation, Types, Uses, Examples
Chemistry in Everyday Life	Drugs, Chemicals, Detergents, Applications

Class 12 Chemistry: Chapter-wise Formula List (Expand for Details)

Note: Only chapters with significant formulas are included.

Physical Chemistry Formulas

Physical Chemistry involves the numerical and conceptual part of Chemistry, including calculations in mole concept, thermodynamics, chemical equilibrium, electrochemistry, and more. Here are some must-know formulas:

Formula/Concept	Explanation
Mole Concept	n = Mass (g)/Molar mass (g/mol)
Avogadro Number	1 mole = 6.022×10²³ particles
Gas Law	PV = nRT
Enthalpy Change	ΔH = ΔU + PΔV
Gibbs Free Energy	ΔG = ΔH - TΔS
Osmotic Pressure	π = CRT
Nernst Equation	E = E° - (0.059/n)logQ
Faraday’s Laws	m = (E×Q)/(F×z)

Organic Chemistry Formulas

Organic Chemistry is based on reaction mechanisms, named reactions, functional groups, and IUPAC nomenclature. Here’s a list of key formulas, rules, and shortcuts for quick revision.

Topic	Summary/Formula
General Formula of Alkanes	CnH₂n+₂
General Formula of Alkenes	CnH₂n
General Formula of Alkynes	CnH₂n-2
Nomenclature	Longest chain, functional group priority, suffix/prefix
SN1/SN2 Reactions	Substitution: SN1 (2 steps, carbocation), SN2 (1 step, inversion)
Electrophilic Addition	Markovnikov’s Rule, Peroxide effect (anti-Markovnikov)
Oxidation/Reduction Reactions	K₂Cr₂O₇, NaBH₄, LiAlH₄, etc.
Important Named Reactions	Aldol, Cannizzaro, Wurtz, Friedel-Crafts, Kolbe, etc.

Inorganic Chemistry Formulas

Inorganic Chemistry deals with periodic table trends, chemical bonding, coordination compounds, and fact-based questions. Use this section for high-yield points:

Concept/Compound	Formula/Key Point
Water	H₂O
Sulphuric Acid	H₂SO₄
Chromate Ion	CrO₄²⁻
Sodium Acetate	CH₃COONa
Zinc Phosphate	Zn₃(PO₄)₂
Types of Salts	Acidic, Basic, Neutral, Double salts
Isotopes/Isobars/Isotones	Isotopes: Same Z, diff A; Isobars: Same A, diff Z; Isotones: Same neutrons

Important Chemistry Definitions

• Chemical Formula: Representation of a molecule/compound using symbols and numbers (e.g., H₂O, CO₂, C₆H₁₂O₆).
• Empirical Formula: Simplest whole-number ratio of atoms in a compound (e.g., CH₂O for glucose).
• Molecular Formula: Actual number of atoms of each element (e.g., C₆H₁₂O₆ for glucose).
• Structural Formula: Graphic representation showing the arrangement of atoms in a molecule.
• Valency: The combining power of an element.
• Acid-Base: pH = -log[H⁺], Buffer, Indicators
• Law of Conservation of Mass: Mass is neither created nor destroyed.
• Tyndall Effect: Scattering of light by colloidal particles.

How to Study Chemistry Formulas Effectively?

• Start every chapter with NCERT/Board textbook theory; jot down all important formulas and reactions in a notebook.
• Revise formulas frequently, especially before tests, using formula sheets and mind maps provided above.
• Practice previous year board/entrance questions and MCQs using these formulas.
• Make flashcards for reactions, conversion steps, and exceptional cases in Organic Chemistry.
• For Inorganic, focus on periodic trends, block elements, and color/magnetic properties.
• Always memorize units and standard values (gas constant, Avogadro number, etc).

Tip: Revisit this page before every test for a quick, high-yield revision!

Frequently Asked Questions (FAQs) – Chemistry Formulas

• Q1. What is the best way to memorize chemistry formulas?
  Make a summary sheet, practice problems, and revise formulas regularly. Use flashcards and mnemonics for tricky ones.
• Q2. Are these formulas useful for JEE and NEET?
  Yes! These cover core CBSE/NCERT formulas asked in JEE, NEET, CUET, Olympiads, and school exams.
• Q3. How are chemical formulas written?
  Use element symbols (Na, Cl, H, O) and indices for the number of atoms (e.g., H₂O, CO₂).
• Q4. Which chapters have the most formulas?
  Mole concept, Thermodynamics, Electrochemistry, Organic reactions, and Coordination compounds.

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