1. Introduction to Hydrocarbons with Examples
What are Hydrocarbons?
Hydrocarbons are organic compounds made up of only carbon (C) and hydrogen (H) atoms.
They are the simplest and most fundamental organic compounds, and serve as the basis for all other organic substances.
Examples of Hydrocarbons
Methane (CH₄)
Ethane (C₂H₆)
Ethene (C₂H₄)
Ethyne (C₂H₂)
Propane (C₃H₈)
Hydrocarbons may be saturated (single bonds only) or unsaturated (double or triple bonds).
2. IUPAC Names, Molecular Structures & Uses of Hydrocarbons (C1 to C4)
2.1 Table: IUPAC Names and Structures
| No. of Carbon Atoms | Hydrocarbon Type | Molecular Formula | IUPAC Name | Structural Formula | Uses |
|---|---|---|---|---|---|
| 1 | Alkane | CH₄ | Methane | H–C–H (4 H around C) | Fuel gas, biogas |
| 2 | Alkane | C₂H₆ | Ethane | H₃C–CH₃ | LPG mixture, petrochemical industry |
| 2 | Alkene | C₂H₄ | Ethene | H₂C=CH₂ | Ripening of fruits, making plastics (polythene) |
| 2 | Alkyne | C₂H₂ | Ethyne | HC≡CH | Used in welding (oxy-acetylene flame) |
| 3 | Alkane | C₃H₈ | Propane | H₃C–CH₂–CH₃ | LPG fuel |
| 4 | Alkane | C₄H₁₀ | Butane | H₃C–CH₂–CH₂–CH₃ | LPG, cigarette lighters |
Summary of Uses
Methane: Domestic fuel, biogas, industrial fuel
Ethane: Used in the petrochemical industry
Ethene: Fruit ripening, plastic manufacture
Ethyne (Acetylene): Welding, cutting metals
Propane & Butane: LPG, heating, cooking
3. Difference Between Saturated and Unsaturated Hydrocarbons
Saturated Hydrocarbons
Contain only single C–C bonds
Known as alkanes
General formula: CₙH₂ₙ₊₂
Less reactive
Examples: Methane (CH₄), Ethane (C₂H₆)
Unsaturated Hydrocarbons
Contain double (C=C) or triple (C≡C) bonds
Two types: Alkenes (double) and Alkynes (triple)
More reactive than saturated hydrocarbons
Examples:
Ethene (C₂H₄ → alkene)
Ethyne (C₂H₂ → alkyne)
Comparison Table
| Feature | Saturated Hydrocarbons | Unsaturated Hydrocarbons |
|---|---|---|
| Bonds | Single bonds only | At least one double or triple bond |
| Types | Alkanes | Alkenes & Alkynes |
| Reactivity | Low | High |
| General Formula | CₙH₂ₙ₊₂ | Alkenes: CₙH₂ₙ Alkynes: CₙH₂ₙ₋₂ |
4. Types and Molecular Formulae of Alcohols Based on Number of Hydroxyl Groups (-OH)
Alcohols are organic compounds containing one or more hydroxyl (-OH) groups attached to carbon atoms.
4.1 Types of Alcohols
| Type of Alcohol | Description | General Formula | Example |
|---|---|---|---|
| Monohydric Alcohol | Contains 1 hydroxyl group (-OH) | CₙH₂ₙ₊₁OH | Methanol (CH₃OH), Ethanol (C₂H₅OH) |
| Dihydric Alcohol | Contains 2 hydroxyl groups (-OH) | CₙH₂ₙ(OH)₂ | Ethylene glycol (C₂H₄(OH)₂) |
| Trihydric Alcohol | Contains 3 hydroxyl groups (-OH) | CₙH₂ₙ₋₁(OH)₃ | Glycerol / Glycerin (C₃H₅(OH)₃) |
5. Uses of Alcohols: Methanol, Ethanol, and Glycerol
5.1 Methanol (CH₃OH) – Uses
Used as an industrial solvent
Used to make dyes, medicines, and resins
Used as antifreeze in vehicles
Used in biodiesel production
Toxic—cannot be consumed
5.2 Ethanol (C₂H₅OH) – Uses
Used in alcoholic beverages (in regulated quantities)
Used as a solvent in perfumes, paints, and medicines
Used as a fuel (ethanol-blended petrol)
Used in hand sanitisers (70% ethanol)
Used in thermometers
5.3 Glycerol / Glycerin (C₃H₅(OH)₃) – Uses
Used in soaps and shampoos
Used in cosmetics and moisturisers
Used as a sweetening agent in the food industry
Used in pharmaceutical syrups
Used to make explosives (nitroglycerin)
Conclusion (SEO-Friendly)
Hydrocarbons and their derivatives form the foundation of organic chemistry. Understanding their classification, IUPAC naming (C1–C4), and differences between saturated and unsaturated hydrocarbons builds strong conceptual clarity for SEE/NEB students. The study of alcohols, their types, and their applications helps learners relate chemistry to real-life uses in medicines, fuels, cosmetics, and industries.
Practice : SEE MCQ: Hydrocarbon and Its Compound
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