Correct option is A
The Correct Answer Is: (A) Have strong covalent bond within molecules but weak intermolecular force
Explanation:
Covalently bonded compounds have strong covalent bonds within individual molecules, meaning that the atoms inside the molecule are tightly held together. However, the intermolecular forces (forces between molecules) are weak, such as van der Waals forces or dipole-dipole interactions.
Since boiling point depends on the energy required to overcome these intermolecular forces, covalent compounds generally have low boiling points because only weak forces need to be broken for them to transition from liquid to gas.
Important Key Points:
- Covalent bonds are strong intramolecular forces (inside molecules).
- Intermolecular forces (between molecules) are weak and include London dispersion forces, dipole-dipole interactions, and hydrogen bonding.
- Low boiling points mean that covalent compounds often exist as gases or liquids at room temperature (e.g., methane, oxygen, water).
- Ionic compounds generally have high boiling points due to strong electrostatic forces between ions.