Concepts Related to Hydrocarbons

Alkanes:

• Saturated hydrocarbons with only single C-C bonds
• Formula: CnH2n+2
• Structures: Acyclic (straight-chain) or cyclic (ring structures)

Alkenes:

• Unsaturated hydrocarbons with at least one C=C double bond
• Formula: CnH2n
• Structures: Acyclic (straight-chain) or cyclic (ring structures)
• Geometric isomerism: Cis-trans isomerism due to the restricted rotation around double bonds

Alkynes:

• Unsaturated hydrocarbons with at least one C≡C triple bond
• Formula: CnH2n-2
• Structures: Acyclic (straight-chain) or cyclic (ring structures)

Aromatic hydrocarbons:

• Cyclic, unsaturated hydrocarbons with alternating C=C double bonds and single C-C bonds
• Formula: (e.g.) C6H6 for benzene, but different for more complex rings.
• Special stability: Due to resonance and the delocalized π-electron cloud
• Reactions: Electrophilic aromatic substitution.

Cycloalkanes:

• Saturated cyclic hydrocarbons with only C-C single bonds
• Formula: CnH2n
• Structures: Can have different conformations, such as chair and boat in cyclohexane

Functionalization of Hydrocarbons

• **Alkanes:**Substitution reactions (halogenation, nitration, sulfonation), combustion, free radical reactions
• Alkenes and alkynes: Addition reactions (hydrogenation, halogens, water, hydrogen halides), electrophilic addition (Markovnikov’s rule), hydration, polymerization, combustion
• Aromatic electrophilic substitution: Nitration, halogenation, sulfonation, Friedel-Crafts reactions.

Additional Concepts:

• Structural isomers (same formula, different connectivity) vs. constitutional isomers (different formulas).
• IUPAC system to name hydrocarbons systematically according to specific rules based on the structure.
• Heats of combustion and enthalpy changes provide insights into energy-related aspects of hydrocarbon reactions.
• Environmental consequences like the greenhouse effect, fossil fuel utilization, and hydrocarbon pollutant impact.