Full Chapter Notes
Short Question
MCQ’s with Exercise
Class 12th Chemistry Chapter – “Aliphatic Hydrocarbons” focuses on the properties, structure, and reactions of aliphatic hydrocarbons, which are organic compounds composed exclusively of carbon and hydrogen atoms. Here’s a brief overview:
Definition
- Aliphatic Hydrocarbons: These are hydrocarbons that consist of straight or branched chains of carbon atoms and can be saturated (alkanes) or unsaturated (alkenes and alkynes).
Types
- Alkanes:
- Structure: Saturated hydrocarbons with single carbon-carbon bonds (C-C).
- General Formula: CₙH₂ₙ₊₂.
- Properties: Generally unreactive, they primarily undergo combustion and substitution reactions.
- Alkenes:
- Structure: Unsaturated hydrocarbons with at least one double bond (C=C).
- General Formula: CₙH₂ₙ.
- Properties: More reactive than alkanes due to the presence of the double bond, they undergo addition reactions.
- Alkynes:
- Structure: Unsaturated hydrocarbons with at least one triple bond (C≡C).
- General Formula: CₙH₂ₙ₋₂.
- Properties: Highly reactive, they also participate in addition reactions.
Properties
- Physical Properties: Aliphatic hydrocarbons are generally non-polar, have low boiling and melting points, and are less dense than water. They are soluble in organic solvents but not in water.
- Chemical Properties: Their reactivity varies with the type of bond (single, double, or triple), affecting their behavior in reactions like combustion, hydrogenation, and halogenation.
Applications
- Aliphatic hydrocarbons are important in various industries, including:
- Fuel: Alkanes like octane are key components of gasoline.
- Plastics: Alkenes are used to produce polymers such as polyethylene.
- Organic Synthesis: They serve as starting materials for synthesizing more complex organic compounds.
This chapter lays the groundwork for understanding the structure, reactions, and significance of aliphatic hydrocarbons in organic chemistry and their applications in real-world scenarios.