Answer
Hydrocarbons: Simple Organic Molecules
The type of molecule characterized by the presence of carbon-hydrogen (C–H) bonds, the absence of functional groups, nonpolarity, and a low boiling point is known as a hydrocarbon.
Definition: Hydrocarbons are organic compounds consisting entirely of carbon and hydrogen atoms. They are the simplest type of organic molecule.
1. Structural Features
- Elements: Composed solely of carbon (C) and hydrogen (H).
- C–H and C–C Bonds: These are nonpolar covalent bonds.
- No Functional Groups: Lacks oxygen, nitrogen, or halogen atoms that would introduce polarity or reactivity.
2. Types of Hydrocarbons
- Alkanes: Saturated hydrocarbons with single bonds only (e.g., methane, ethane).
- Alkenes: Unsaturated hydrocarbons with one or more double bonds (e.g., ethene).
- Alkynes: Unsaturated hydrocarbons with one or more triple bonds (e.g., ethyne).
- Aromatic Hydrocarbons: Contain benzene rings or similar structures (e.g., benzene, toluene).
3. Physical Properties
- Nonpolar: Since C–H and C–C bonds have minimal electronegativity differences, hydrocarbons are nonpolar.
- Insoluble in Water: Due to their nonpolarity, they do not dissolve well in polar solvents like water.
- Low Boiling Points: Weak van der Waals (London dispersion) forces result in low boiling and melting points, especially in smaller hydrocarbons.
- Volatile: Many hydrocarbons are gases or liquids at room temperature and easily evaporate.
4. Uses and Applications
- Fuels: Hydrocarbons such as propane, butane, gasoline, and natural gas are widely used as energy sources.
- Solvents: Some nonpolar solvents used in industry and laboratories are hydrocarbon-based (e.g., hexane).
- Raw Materials: Used in the production of plastics, synthetic fibers, and other chemicals.
Conclusion: Molecules with only carbon and hydrogen, lacking functional groups, and exhibiting nonpolar characteristics and low boiling points are classified as hydrocarbons. Their simple structure and inert nature make them essential in various industrial applications.