Organic Chemistry: Hydrocarbons

Definition and Classification

• Hydrocarbons are organic compounds consisting of only hydrogen (H) and carbon (C) atoms.
• Classified into two main categories:
  • Saturated hydrocarbons (alkanes): single bonds between carbon atoms, general formula CnH2n+2.
  • Unsaturated hydrocarbons (alkenes and alkynes): double or triple bonds between carbon atoms, general formula CnH2n (alkenes) and CnH2n-2 (alkynes).

Saturated Hydrocarbons (Alkanes)

• General properties:
  • Non-polar, non-reactive, and non-electrolytes.
  • Low boiling points, increasing with molecular weight.
  • Insoluble in water, soluble in organic solvents.
• Examples:
  • Methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10).

Unsaturated Hydrocarbons (Alkenes and Alkynes)

• General properties:
  • Polar, reactive, and non-electrolytes.
  • Higher boiling points than alkanes, decreasing with molecular weight.
  • Insoluble in water, soluble in organic solvents.
• Examples:
  • Ethene (C2H4), propene (C3H6), but-1-ene (C4H8) (alkenes).
  • Ethyne (C2H2), propyne (C3H4), but-1-yne (C4H6) (alkynes).

Isomerism in Hydrocarbons

• Structural isomerism: same molecular formula, different arrangements of atoms.
• Stereoisomerism: same molecular formula and bond sequence, different 3D arrangements.

Uses of Hydrocarbons

• Energy sources: fuels for transportation, heating, and electricity generation.
• Feedstock for chemical synthesis: plastics, fertilizers, pharmaceuticals, and dyes.
• Intermediates in industrial processes: lubricants, solvents, and adhesives.

Hydrocarbons

• Defined as organic compounds consisting only of hydrogen (H) and carbon (C) atoms.

Classification of Hydrocarbons

• Divided into two main categories: saturated and unsaturated hydrocarbons.

Saturated Hydrocarbons (Alkanes)

• Characterized by single bonds between carbon atoms.
• General formula: CnH2n+2.
• Properties:
  • Non-polar, non-reactive, and non-electrolytes.
  • Low boiling points, increasing with molecular weight.
  • Insoluble in water, soluble in organic solvents.
• Examples:
  • Methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10).

Unsaturated Hydrocarbons (Alkenes and Alkynes)

• Characterized by double or triple bonds between carbon atoms.
• General formulas: CnH2n (alkenes) and CnH2n-2 (alkynes).
• Properties:
  • Polar, reactive, and non-electrolytes.
  • Higher boiling points than alkanes, decreasing with molecular weight.
  • Insoluble in water, soluble in organic solvents.
• Examples:
  • Alkenes: ethene (C2H4), propene (C3H6), but-1-ene (C4H8).
  • Alkynes: ethyne (C2H2), propyne (C3H4), but-1-yne (C4H6).

Isomerism in Hydrocarbons

• Structural isomerism: same molecular formula, different arrangements of atoms.
• Stereoisomerism: same molecular formula and bond sequence, different 3D arrangements.

Uses of Hydrocarbons

• Energy sources: fuels for transportation, heating, and electricity generation.
• Feedstock for chemical synthesis: plastics, fertilizers, pharmaceuticals, and dyes.
• Intermediates in industrial processes: lubricants, solvents, and adhesives.