Schooling · Class 10 · Science · Carbon and its Compounds · Chapter on a page
CBSE Class 10 · Science · NCERT Science
Carbon and its Compounds: chapter on a page
A cut of Shishya's notes for this chapter: the first paragraph of the introduction and the key ideas, formulas and facts, common mistakes and quick revision lists, word for word. Nothing is added or reworded; the worked examples are left out (they are on the chapter page).
About the notes: Written by Shishya's AI on 26 Sept 2026 from the chapter's title and class level, in Shishya's own words — not a copy or summary of the textbook. Read the official chapter for the book's own text, activities and exercises.
This note's current text has no applied fact-check on record.
Mind map
Drawn from the same notes by a fixed rule (no AI): each label is the item's own words — its bold term, its label before a colon, a short formula as written, or its first words.
The mind map as a list
- Key ideas
- Carbon has a valency of four…
- Covalent bonds form when atoms share…
- Catenation is the unique ability of…
- Hydrocarbons are compounds…
- A homologous series is a family of…
- Functional groups like –OH…
- Ethanol (C₂H₅OH) is a common alcohol…
- Formulas and facts
- General formula of alkanes
- General formula of alkenes
- General formula of alkynes
- Combustion of hydrocarbons
- Addition reaction
- Substitution reaction
- Esterification
- Watch out for
- Thinking carbon forms ionic bonds…
- Writing wrong number of bonds for…
- Confusing saturated and unsaturated…
- Forgetting to balance oxygen atoms…
- Mixing up ethanol and ethanoic acid
What this chapter is about
Carbon is a unique element that forms the basis of all living organisms and countless useful materials around us. This chapter explores why carbon can form an enormous variety of compounds — far more than any other element — and introduces the branch of chemistry dealing with these compounds, called organic chemistry.
Key ideas
- Carbon has a valency of four, meaning each carbon atom can form four covalent bonds with other atoms, allowing it to make complex and stable molecules.
- Covalent bonds form when atoms share electrons rather than transferring them; carbon compounds typically have covalent bonds and hence low melting points, do not conduct electricity, and are generally poor conductors of heat.
- Catenation is the unique ability of carbon atoms to bond with other carbon atoms, forming long chains, branched chains, and ring structures.
- Hydrocarbons are compounds containing only carbon and hydrogen; saturated hydrocarbons (alkanes) have single bonds only, while unsaturated hydrocarbons (alkenes and alkynes) have double or triple bonds.
- A homologous series is a family of compounds with the same functional group, similar chemical properties, and a regular difference of CH₂ in molecular formula between successive members.
- Functional groups like –OH (alcohol), –COOH (carboxylic acid), and –CHO (aldehyde) determine the chemical properties of organic compounds.
- Ethanol (C₂H₅OH) is a common alcohol used in beverages, medicines and as a fuel, while ethanoic acid (CH₃COOH) is the acid present in vinegar.
Formulas and facts to remember
- General formula of alkanes: CₙH₂ₙ₊₂ (for example, methane CH₄, ethane C₂H₆, propane C₃H₈).
- General formula of alkenes: CₙH₂ₙ (for example, ethene C₂H₄, propene C₃H₆).
- General formula of alkynes: CₙH₂ₙ₋₂ (for example, ethyne C₂H₂, propyne C₃H₄).
- Combustion of hydrocarbons: Hydrocarbon + Oxygen → Carbon dioxide + Water + Heat. Complete combustion gives a blue flame; incomplete combustion produces soot (carbon) and carbon monoxide.
- Addition reaction: Unsaturated hydrocarbons add hydrogen in presence of a catalyst (nickel or palladium) to become saturated. Example: C₂H₄ + H₂ → C₂H₆ (ethene to ethane).
- Substitution reaction: Saturated hydrocarbons undergo substitution; for example, methane reacts with chlorine in sunlight: CH₄ + Cl₂ → CH₃Cl + HCl.
- Esterification: Alcohol + Carboxylic acid → Ester + Water. This reaction occurs in presence of an acid catalyst.
- Saponification: Fat or oil + Sodium hydroxide → Soap + Glycerol. This is the process of making soap.
- Denatured alcohol: Ethanol made unfit for drinking by adding poisonous substances like methanol or copper sulphate.
Common mistakes
- Thinking carbon forms ionic bonds like sodium → Carbon shares electrons to form covalent bonds because it has four valence electrons, making it easier to share than gain or lose.
- Writing wrong number of bonds for carbon → Always check that each carbon atom makes exactly four bonds in structural formulas.
- Confusing saturated and unsaturated hydrocarbons → Saturated means only single bonds (alkanes); unsaturated means double or triple bonds (alkenes, alkynes).
- Forgetting to balance oxygen atoms last in combustion equations → Balance C first, then H, then count total oxygen needed on the product side.
- Mixing up ethanol and ethanoic acid → Ethanol (C₂H₅OH) is an alcohol; ethanoic acid (CH₃COOH) is a carboxylic acid with sour taste and acidic properties.
Quick revision
- Carbon has valency 4 and forms covalent bonds by sharing electrons.
- Catenation allows carbon to form chains, branches and rings with other carbon atoms.
- Alkanes are saturated (CₙH₂ₙ₊₂); alkenes and alkynes are unsaturated.
- Functional groups like –OH, –COOH, and –CHO give organic compounds their characteristic properties.
- Addition reactions convert unsaturated compounds to saturated; substitution reactions occur in saturated compounds.
- Soaps are sodium or potassium salts of long-chain carboxylic acids, made by saponification.