
Topics Discussed
1. Introduction to Carbon
- Elemental Form: Carbon is a non-metal with the symbol C and atomic number 6.
- Occurrence: It is found in nature in both free (e.g., diamond, graphite) and combined states (e.g., carbon dioxide, hydrocarbons).
- Versatility: Carbon forms a large number of compounds due to its unique properties.
2. Unique Properties of Carbon
- Catenation: Carbon can form long chains or rings by bonding with other carbon atoms.
- Tetravalency: Carbon has 4 valence electrons, allowing it to form 4 covalent bonds.
- Multiple Bonding: Carbon can form single, double, or triple bonds with other atoms.
- Isomerism: Carbon compounds can exist in different structural forms with the same molecular formula.
3. Allotropes of Carbon
Allotropes are different forms of the same element with varying physical properties.
- Diamond:
- Hardest natural substance.
- Each carbon atom is bonded to 4 other carbon atoms in a tetrahedral structure.
- Poor conductor of electricity.
- Graphite:
- Soft and slippery.
- Each carbon atom is bonded to 3 others, forming hexagonal layers.
- Good conductor of electricity.
- Fullerenes:
- Spherical or cylindrical structures (e.g., C60, Buckminsterfullerene).
- Used in nanotechnology and medicine.
4. Covalent Bonding in Carbon Compounds
- Covalent Bond: Formed by sharing electrons between atoms.
- Types of Covalent Bonds:
- Single Bond (C-C)
- Double Bond (C=C)
- Triple Bond (C≡C)
- Examples:
- Methane (CH₄): Single bonds.
- Ethene (C₂H₄): Double bond.
- Ethyne (C₂H₂): Triple bond.
5. Hydrocarbons
Compounds made of hydrogen and carbon atoms.
- Types:
- Saturated Hydrocarbons (Alkanes):
- Single bonds between carbon atoms.
- General formula: CₙH₂ₙ₊₂.
- Example: Methane (CH₄), Ethane (C₂H₆).
- Unsaturated Hydrocarbons:
- Alkenes: Contain at least one double bond. General formula: CₙH₂ₙ. Example: Ethene (C₂H₄).
- Alkynes: Contain at least one triple bond. General formula: CₙH₂ₙ₋₂. Example: Ethyne (C₂H₂).
6. Functional Groups
A group of atoms that determine the chemical properties of a compound.
- Common Functional Groups:
- Alcohol (-OH): Example: Ethanol (C₂H₅OH).
- Aldehyde (-CHO): Example: Ethanal (CH₃CHO).
- Carboxylic Acid (-COOH): Example: Acetic Acid (CH₃COOH).
- Ketone (-CO-): Example: Acetone (CH₃COCH₃).
- Haloalkane (-X): Example: Chloromethane (CH₃Cl).
7. Homologous Series
A series of compounds with the same functional group and similar chemical properties.
- Characteristics:
- Same general formula.
- Gradual change in physical properties.
- Similar chemical reactions.
- Example: Alkanes (CₙH₂ₙ₊₂), Alcohols (CₙH₂ₙ₊₁OH).
8. Chemical Properties of Carbon Compounds
- Combustion:
- Hydrocarbons burn in oxygen to produce CO₂, H₂O, and energy.
- Example: CH₄ + 2O₂ → CO₂ + 2H₂O + Energy.
- Oxidation:
- Alcohols can be oxidized to form aldehydes or carboxylic acids.
- Example: Ethanol → Ethanal → Acetic Acid.
- Addition Reaction:
- Unsaturated hydrocarbons (alkenes, alkynes) add hydrogen or halogens.
- Example: C₂H₄ + H₂ → C₂H₆.
- Substitution Reaction:
- Hydrogen atoms in alkanes are replaced by other atoms.
- Example: CH₄ + Cl₂ → CH₃Cl + HCl.
9. Important Carbon Compounds
- Ethanol (C₂H₅OH):
- Used in alcoholic beverages, solvents, and fuels.
- Reacts with sodium to release hydrogen gas.
- Ethanoic Acid (CH₃COOH):
- Commonly known as acetic acid.
- Used in vinegar and as a preservative.
- Reacts with bases to form salts (e.g., sodium acetate).
10. Soaps and Detergents
- Soap:
- Sodium or potassium salts of fatty acids.
- Cleansing action due to micelle formation.
- Detergents:
- Synthetic cleansing agents.
- Effective in hard water.
11. Environmental Impact
- Carbon Cycle: Movement of carbon between the atmosphere, oceans, and living organisms.
- Greenhouse Effect: CO₂ and other gases trap heat, leading to global warming.
- Air Pollution: Combustion of fossil fuels releases CO₂, CO, and other pollutants.
12. Summary
- Carbon forms a vast number of compounds due to catenation and tetravalency.
- Hydrocarbons are classified into alkanes, alkenes, and alkynes.
- Functional groups determine the properties of organic compounds.
- Carbon compounds play a vital role in daily life and the environment.
These notes provide a comprehensive overview of the Carbon and Its Compounds chapter for Class 10. Let me know if you need further clarification!