Carbon and Its Compounds — Made Simple

Master Class 10 Carbon and Its Compounds: covalent bonding, catenation, homologous series, functional groups, IUPAC naming, and key reactions like combustion, addition and esterification.

By the PadhoDost Team · 📖 8 min read · Updated 4 August 2026

Part of Class 10 (CBSE) prep

🧠 Carbon, the Ultimate Lego Block

Imagine a Lego brick with exactly four studs that can click onto four other bricks — and those bricks can click onto more, endlessly, in straight lines, branches or rings. That is carbon. Because each carbon atom can bond to four others (including other carbons), it builds millions of different structures. This is why almost everything living — food, fuel, plastic, medicine — is built around carbon.

Why Carbon Forms So Many Compounds

C H H H H Methane · CH₄
Carbon forms four covalent bonds — as in methane (CH₄), one carbon sharing with four hydrogens.

Carbon has atomic number 6, so its electron arrangement is 2,4 — four electrons in the outer shell. To become stable it would need to gain or lose four electrons, which takes too much energy. Instead, carbon shares its four electrons, forming covalent bonds. Two special abilities follow: tetravalency (it always forms four bonds) and catenation (carbon atoms link to one another to form long chains, branched chains and rings). Together these give carbon an enormous family of compounds.

SeriesGeneral FormulaBond TypeExample
AlkanesCnH2n+2Single bonds (saturated)Methane CH4, Ethane C2H6
AlkenesCnH2nOne C=C double bondEthene C2H4
AlkynesCnH2n-2One C triple-bond CEthyne C2H2
Alkane: CnH2n+2 | Alkene: CnH2n | Alkyne: CnH2n-2 | Any two neighbours in a homologous series differ by one CH2 unit (a mass difference of 14 u)

Functional Groups & Naming

A functional group is an atom or group of atoms that gives a compound its special properties. The carbon chain is named with a root (meth = 1 carbon, eth = 2, prop = 3, but = 4) plus a suffix. Saturated compounds end in -ane. A functional group is shown by a prefix or suffix — for example -ol for alcohols (ethanol) and -oic acid for carboxylic acids (ethanoic acid).

Functional GroupFormulaFamilyExample
Halo-Cl, -BrHaloalkaneChloroethane C2H5Cl
Alcohol-OHAlcoholEthanol C2H5OH
Aldehyde-CHOAldehydeEthanal CH3CHO
Ketone-CO-KetonePropanone CH3COCH3
Carboxylic acid-COOHCarboxylic acidEthanoic acid CH3COOH

The Reactions That Matter

Combustion: carbon compounds burn in air to give CO2, water, heat and light, e.g. CH4 + 2O2 -> CO2 + 2H2O. Oxidation: alcohols can be oxidised to carboxylic acids by alkaline KMnO4 or acidified K2Cr2O7. Addition: unsaturated hydrocarbons add hydrogen across the double/triple bond using a nickel catalyst — this hydrogenation converts liquid vegetable oils into solid vanaspati. Substitution: in sunlight, alkanes like methane react with chlorine, where Cl replaces H one at a time (CH4 + Cl2 -> CH3Cl + HCl). Esterification: a carboxylic acid + an alcohol, with a little concentrated H2SO4, give a sweet-smelling ester used in perfumes and flavours.

📝 Worked Example: Name and Formula

Question: Find the molecular formula and name of the alkane with 3 carbon atoms.

Alkanes follow the general formula CnH2n+2.

Put n = 3: hydrogen atoms = 2(3) + 2 = 8.

So the molecular formula is C3H8.

Root for 3 carbons = 'prop'; saturated (single bonds) suffix = '-ane'.

Name = Propane (the gas used in LPG cylinders).

Remember These

  • Carbon is tetravalent and shows catenation, so it forms covalent compounds in huge numbers.
  • Saturated = only single bonds (alkanes); unsaturated = a double or triple bond (alkenes, alkynes).
  • Members of a homologous series differ by CH2 (14 u) and share the same functional group.
  • Addition reactions need unsaturation + a catalyst (Ni); substitution reactions are typical of saturated alkanes.
  • Acid + alcohol -> ester + water is esterification (sweet smell); ester + NaOH -> soap is saponification.

⚡ Quick check

Which of the following is an unsaturated hydrocarbon?

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