A fast, one-glance recap of Class 10 Science Chapter 4 (Carbon and its Compounds) — for full worked explanations, see the Solutions.
Revision Notes: Carbon and its Compounds
- Covalent bonding: carbon has 4 valence electrons, shares electrons (rather than gaining/losing 4) to complete its octet, forming strong covalent bonds
- Allotropes of carbon: diamond (rigid tetrahedral network, hardest natural substance), graphite (hexagonal layers, soft, conducts electricity), fullerenes
- Saturated hydrocarbons (alkanes): C–C single bonds only, general formula CₙH₂ₙ⁺₂
- Unsaturated hydrocarbons: alkenes (C=C, CₙH₂ₙ), alkynes (C≡C, CₙH₂ₙ−₂)
- Homologous series: same general formula, similar chemical properties, each member differs by –CH₂– (14u)
- Functional groups: –OH (alcohol), –COOH (carboxylic acid), –CHO (aldehyde), >C=O (ketone), –X (halide)
- Test for unsaturation: bromine water decolourised = unsaturated; no change = saturated
- Combustion: complete (blue flame, CO₂+H₂O) vs incomplete (yellow sooty flame, CO + soot)
- Oxidation: alcohols → carboxylic acids (using alkaline KMnO₄ or acidified K₂Cr₂O₉)
- Addition reaction (hydrogenation): unsaturated + H₂ (Ni catalyst) → saturated (vegetable oil → vanaspati ghee)
- Substitution reaction: saturated hydrocarbons + halogen (sunlight) → halogen replaces H atoms one by one
- Esterification: alcohol + carboxylic acid (acid catalyst) → ester (sweet smell) + water
- Soap: sodium/potassium salt of a long-chain fatty acid; hydrophilic head + hydrophobic tail; forms micelles to trap dirt
- Hard water + soap → scum (insoluble Ca/Mg salts of fatty acids); detergents work even in hard water
Related: Solutions | Extra Questions | Revision Notes | Formulas Handbook | Class 10 Science Book
