The correct option is Poor conductors of electricity.
Explanation
Carbon compounds are formed primarily through covalent bonding, which involves the sharing of valence electrons between atoms to achieve a stable electronic configuration. Unlike ionic bonds, where electrons are transferred to create charged species, covalent bonds result in the formation of discrete, electrically neutral molecules.
Option Analysis
- Poor conductors of electricity is Correct: The conduction of electricity requires the presence of free-moving charge carriers, such as electrons or ions. In covalently bonded carbon compounds, electrons are shared between atoms and are not free to move. Furthermore, these compounds do not dissociate into ions. Consequently, they are generally poor conductors of electricity.
- Good electrolytes in water is Incorrect: Electrolytes are substances that dissociate into ions when dissolved in water, allowing the solution to conduct electricity. Most covalent carbon compounds (e.g., glucose, alcohol) do not dissociate into ions in water and are therefore non-electrolytes.
- Separable into ions on melting is Incorrect: When covalent compounds melt, the energy supplied overcomes the weak intermolecular forces (Van der Waals forces) between the molecules, not the strong covalent bonds within the molecules. Therefore, the liquid state consists of neutral molecules, not ions.
- Metallic conductors is Incorrect: Metallic conductors rely on a lattice of positive kernels immersed in a sea of delocalized electrons. Carbon compounds do not possess this metallic bonding structure. While graphite (an allotrope of elemental carbon) is a conductor, this is a specific exception due to its layered structure and is not a general property of carbon compounds.
Key Takeaway: Covalent carbon compounds consist of neutral molecules held together by electron sharing. Due to the absence of free ions or free electrons, they are generally poor conductors of electricity and do not exhibit electrolytic behavior.