Chemistry Formulas for Class 12 — Complete Formula Sheet 2026
All Chemistry formulas for Class 12 CBSE and competitive exams — Physical, Organic, Inorganic organised chapter-wise for quick reference.
This is your complete Class 12 Chemistry formula sheet — organised by chapter. Bookmark this page and review it daily. Physical Chemistry formulas are the most numerical-heavy; Organic has more reactions than formulas; Inorganic is mostly factual.
Physical Chemistry Formulas
Solutions (Chapter 1)
| Formula | Description |
|---|---|
| Molarity (M) = moles of solute / volume of solution (L) | Concentration in mol/L |
| Molality (m) = moles of solute / mass of solvent (kg) | Concentration independent of temperature |
| Raoult's Law: P = P°A × xA + P°B × xB | Vapour pressure of ideal solution |
| ΔTb = Kb × m × i | Boiling point elevation |
| ΔTf = Kf × m × i | Freezing point depression |
| π = iCRT | Osmotic pressure |
| i = 1 + (n−1)α | van't Hoff factor (dissociation) |
| i = 1 − α + α/n | van't Hoff factor (association) |
Electrochemistry (Chapter 2)
| Formula | Description |
|---|---|
| E°cell = E°cathode − E°anode | Standard cell potential |
| ΔG° = −nFE°cell | Gibbs energy from cell potential |
| Nernst: E = E° − (RT/nF) ln Q | Cell potential at non-standard conditions |
| Nernst (at 25°C): E = E° − (0.0591/n) log Q | Simplified Nernst equation |
| Λm = κ × 1000 / M | Molar conductivity |
| Kohlrausch: Λ°m = λ°+ + λ°− | Limiting molar conductivity |
| Faraday: m = (M × I × t) / (n × F) | Mass deposited in electrolysis |
Chemical Kinetics (Chapter 3)
| Formula | Description |
|---|---|
| Rate = k[A]ⁿ[B]ᵐ | Rate law expression |
| Zero order: [A] = [A]₀ − kt | Concentration vs time |
| First order: k = (2.303/t) log([A]₀/[A]) | First order rate constant |
| t½ = 0.693/k (first order) | Half-life (independent of concentration) |
| t½ = [A]₀/2k (zero order) | Half-life (depends on initial concentration) |
| Arrhenius: k = Ae^(−Ea/RT) | Rate constant vs temperature |
| log(k₂/k₁) = (Ea/2.303R)(1/T₁ − 1/T₂) | Two-temperature Arrhenius form |
Thermodynamics & Equilibrium
| Formula | Description |
|---|---|
| ΔG = ΔH − TΔS | Gibbs free energy |
| ΔG° = −RT ln K | Gibbs energy and equilibrium constant |
| ΔG° = −2.303RT log K | Log form |
| Kp = Kc(RT)^Δn | Relation between Kp and Kc |
| pH = −log[H⁺] | pH definition |
| pOH = −log[OH⁻] | pOH definition |
| pH + pOH = 14 (at 25°C) | Water equilibrium |
| pH = pKa + log([A⁻]/[HA]) | Henderson-Hasselbalch equation |
Test these formulas with problems
Super Tutor has chapter-wise Chemistry numericals for Class 12 — practise applying formulas, not just reading them.
Start Chemistry Practice — FreeOrganic Chemistry — Key Reactions & Rules
Named Reactions (Board Favourites)
| Reaction | What It Does |
|---|---|
| Sandmeyer Reaction | ArN₂⁺ + CuX → ArX (Cl, Br, CN) |
| Kolbe's Reaction | Phenol + NaOH + CO₂ → Salicylic acid |
| Reimer-Tiemann Reaction | Phenol + CHCl₃ + NaOH → Salicylaldehyde |
| Williamson Synthesis | R-ONa + R'-X → R-O-R' (ether) |
| Aldol Condensation | Aldehyde with α-H + dil. NaOH → β-hydroxy aldehyde |
| Cannizzaro Reaction | Aldehyde without α-H + conc. NaOH → acid + alcohol |
| Hell-Volhard-Zelinsky | Carboxylic acid + Br₂/P → α-bromo acid |
| Hofmann Bromamide | RCONH₂ + Br₂ + NaOH → RNH₂ (−1 carbon) |
| Gabriel Phthalimide | Phthalimide + R-X + KOH → primary amine |
| Coupling Reaction | ArN₂⁺Cl⁻ + ArOH/ArNH₂ → Azo dye |
Reagent-Based Conversions
| Conversion | Reagent |
|---|---|
| Alcohol → Aldehyde | PCC or Collins reagent (mild oxidation) |
| Alcohol → Carboxylic acid | KMnO₄ or K₂Cr₂O₇ (strong oxidation) |
| Aldehyde → Alcohol | NaBH₄ or LiAlH₄ (reduction) |
| Carboxylic acid → Alcohol | LiAlH₄ (strong reduction) |
| Alkyl halide → Alcohol | Aq. NaOH (SN2 for 1°) |
| Amine → Diazonium salt | NaNO₂ + HCl at 0–5°C |
Inorganic Chemistry — Key Facts
| Topic | Key Formula/Fact |
|---|---|
| Crystal Field Splitting | Δo (octahedral) > Δt (tetrahedral); Δt ≈ 4/9 Δo |
| Magnetic Moment | μ = √(n(n+2)) BM, where n = unpaired electrons |
| Coordination Number | CN 4: tetrahedral/square planar; CN 6: octahedral |
| EAN Rule | EAN = Z − oxidation state + 2 × coordination number |
| Lattice Energy | Born-Landé equation; ∝ charge, ∝ 1/distance |
How to Use This Formula Sheet
- Print or bookmark. Review for 15 minutes every morning.
- After each formula, solve 2–3 numericals. Reading ≠ learning. Solving = learning.
- Make your own handwritten sheet. Writing activates motor memory — much stronger than reading.
- Before the exam: write the top 20 formulas from memory on rough paper. This "brain dump" prevents blanking out.
Formulas based on NCERT Class 12 Chemistry (2025–2026 syllabus). Some symbols simplified for readability. For complete derivations, refer to NCERT textbooks. Useful for CBSE boards, JEE Main, and NEET. Last updated: February 2026.
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Start preparing — freeFrequently Asked Questions
How many formulas are there in Class 12 Chemistry?
Approximately 80–100 key formulas across Physical, Organic, and Inorganic Chemistry. Physical Chemistry has the most formulas (50+). Organic Chemistry has fewer formulas but more named reactions (20+). Inorganic Chemistry is more fact-based than formula-based. Focus on the 40–50 most frequently tested formulas first.
Which Chemistry formulas are most important for boards?
Top priority: Nernst equation, Kohlrausch law, rate law expressions, Arrhenius equation, Raoult's law, van't Hoff factor, pH/pOH formulas, crystal field splitting energy. These appear in numericals worth 3–5 marks. For Organic: IUPAC naming rules and reagent-based reactions are more important than formulas.
How to memorise Chemistry formulas?
Write each formula 5 times by hand. Understand what each symbol represents (do not just memorise the letters). Solve 3–5 numericals per formula immediately. Use spaced repetition: revise Day 1, Day 3, Day 7, Day 14. Group related formulas together (e.g., all colligative property formulas). Make a 2-page formula sheet and review it daily.
Are these formulas enough for JEE and NEET?
These cover the NCERT syllabus which is the foundation for both JEE and NEET. JEE may require additional formulas from advanced reference books (e.g., advanced electrochemistry, complex equilibrium). NEET Chemistry is primarily NCERT-based, so these formulas are sufficient. Always supplement with PYQ practice.