CBSE Class 10 Science: Carbon & Its Compounds — Notes 2026

Bonding in Carbon

• Carbon: atomic number 6; electronic configuration 2,4; forms 4 covalent bonds
• Catenation and tetravalency: ability to form chains, branches, rings
• Allotropes of carbon: diamond (tetrahedral network), graphite (layered), C₆₀ fullerene (soccer ball)

Hydrocarbons

• Saturated (alkanes): C−C single bonds; CₙH₂ₙ₊₂; e.g., methane, ethane
• Unsaturated: alkenes (C=C), alkynes (C≡C); more reactive than alkanes
• Bromine water test: alkenes decolourise orange Br₂ water (addition reaction)

Functional Groups

• −OH (alcohols), −COOH (carboxylic acids), −CHO (aldehydes), −CO− (ketones)
• Halogens (−X), amines (−NH₂), esters (−COO−)
• Homologous series: same functional group, CₙH₂ₙ₊₁ prefix changes

Ethanol (Ethyl Alcohol)

• Formula C₂H₅OH; produced by fermentation of sugars/starch with yeast
• Reactions: combustion (clean fuel), oxidation to ethanoic acid, reaction with Na
• Uses: solvent, antiseptic, beverages; denatured alcohol prevents consumption

Ethanoic Acid (Acetic Acid)

• Formula CH₃COOH; weak acid; turns litmus red; found in vinegar (~5%)
• Reactions: with Na metal (H₂↑), with NaOH (neutralisation), with Na₂CO₃ (CO₂↑), with ethanol (esterification)
• Ester formed: ethyl ethanoate CH₃COOC₂H₅; sweet fruity smell

Soaps and Detergents

• Soap: sodium or potassium salt of higher fatty acid (stearic, palmitic, oleic acid)
• Cleansing action: micelle formation; hydrophobic tail surrounds grease; hydrophilic head in water
• Detergents work in hard water (no scum); soaps form scum with Ca²⁺/Mg²⁺ in hard water

CBSE Exam — Carbon Compounds

• Name the compound formed by reaction of ethanol and ethanoic acid; give uses
• Why does carbon form a very large number of compounds?
• Draw structures of: ethane, ethene, ethyne, methanol, ethanoic acid