CBSE · Class 10
Chemistry Formulas for Class 10
Chapter-wise Chemistry formulas, reactions and key equations for CBSE Class 10 (2026-27) — Acids & Bases, Metals & Non-Metals, Carbon Compounds.
For reference only. Always verify formulas and information against your official NCERT textbooks or board-prescribed materials before use in exams. Learnizo does not guarantee absolute accuracy.
Ch 1.Chemical Reactions and Equations
| Formula / Relation | Expression |
|---|---|
| Combination reaction | A + B → AB |
| Decomposition reaction | AB → A + B |
| Displacement reaction | A + BC → AC + B |
| Double displacement | AB + CD → AD + CB |
| Redox reaction | Oxidation (loss of e⁻) + Reduction (gain of e⁻) occur simultaneously |
| Thermal decomposition of CaCO₃ | CaCO₃ → CaO + CO₂ |
| Photosynthesis | 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (sunlight, chlorophyll) |
| Respiration | C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy |
Ch 2.Acids, Bases and Salts
| Formula / Relation | Expression |
|---|---|
| pH scale | 0–14; pH < 7 acidic; pH 7 neutral; pH > 7 basic |
| Neutralisation | Acid + Base → Salt + Water |
| Acid + Metal | Metal + Dilute acid → Salt + H₂↑ |
| Acid + Metal carbonate | Metal carbonate + acid → Salt + H₂O + CO₂↑ |
| Acid + Metal oxide | Metal oxide + acid → Salt + Water |
| Base + Non-metal oxide | NaOH + CO₂ → Na₂CO₃ + H₂O |
| Washing soda | Na₂CO₃·10H₂O |
| Baking soda | NaHCO₃ |
| Bleaching powder | CaOCl₂ (Ca(OCl)Cl) |
| Plaster of Paris | CaSO₄·½H₂O |
Ch 3.Metals and Non-Metals
| Formula / Relation | Expression |
|---|---|
| Metal + Oxygen | 4Na + O₂ → 2Na₂O; 2Mg + O₂ → 2MgO |
| Metal + Water (very reactive) | 2Na + 2H₂O → 2NaOH + H₂↑ |
| Metal + Steam (moderately reactive) | 3Fe + 4H₂O → Fe₃O₄ + 4H₂ |
| Thermite reaction | Fe₂O₃ + 2Al → Al₂O₃ + 2Fe + heat |
| Electrolytic refining anode mud | Impure metal (anode) → pure metal (cathode) + impurities settle at anode |
| Reactivity series (top 5) | K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au |
Ch 4.Carbon and its Compounds
| Formula / Relation | Expression |
|---|---|
| General alkane formula | CₙH₂ₙ₊₂ |
| General alkene formula | CₙH₂ₙ |
| General alkyne formula | CₙH₂ₙ₋₂ |
| Ethanol (alcohol) | C₂H₅OH (CH₃CH₂OH) |
| Ethanoic acid (acetic acid) | CH₃COOH |
| Saponification | Ester + NaOH → Soap (sodium salt of fatty acid) + Glycerol |
| Esterification | Alcohol + Carboxylic acid ⇌ Ester + Water (H⁺ catalyst) |
| Combustion of ethanol | C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O |
Frequently Asked Questions
What is the reactivity series and why is it important?
The reactivity series is a list of metals arranged in decreasing order of reactivity: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au. It predicts displacement reactions (a metal higher in the series displaces one lower), explains why gold and silver are used in jewellery (unreactive), and explains metal extraction methods.
What is the difference between baking soda and washing soda?
Baking soda is NaHCO₃ (sodium hydrogen carbonate) — used in cooking and medicine. Washing soda is Na₂CO₃·10H₂O (sodium carbonate decahydrate) — used for cleaning and softening hard water. Baking soda is weakly basic; washing soda is more strongly alkaline.
What are the general formulas for alkane, alkene and alkyne?
Alkane: CₙH₂ₙ₊₂ (single bonds only; e.g. methane CH₄, ethane C₂H₆). Alkene: CₙH₂ₙ (one double bond; e.g. ethene C₂H₄). Alkyne: CₙH₂ₙ₋₂ (one triple bond; e.g. ethyne C₂H₂). Each series has a consistent difference of CH₂ between successive members (homologous series).
Related resources
Need help with Class 10 Chemistry?
Learnizo tutors cover every reaction and formula with board-pattern practice questions.
Find a Science Tutor