Covalent compounds have low melting points because

Options

A. Covalent bond is less exothermic
B. Covalent molecules have definite shape
C. Covalent bond is weaker than ionic bond
D. Cavalent molecules are held by weak Vander Waal's forces

Answer

### Step-by-Step Solution:

1. **Understanding Covalent Compounds**:
- Covalent compounds are formed when two or more nonmetals share electrons to achieve a full outer shell of electrons. This sharing creates covalent bonds.

2. **Comparing with Ionic Compounds**:
- Ionic compounds are formed from the electrostatic attraction between positively and negatively charged ions. This results in strong ionic bonds due to the significant force of attraction between the oppositely charged ions.

3. **Melting Points of Ionic vs. Covalent Compounds**:
- Ionic compounds typically have high melting points because of the strong electrostatic forces that hold the ions together in a lattice structure. A large amount of energy is required to break these strong bonds.

4. **Forces in Covalent Compounds**:
- In contrast, covalent compounds are held together by covalent bonds, but the forces between individual molecules (intermolecular forces) are relatively weak. These include Van der Waals forces (dispersion forces) and dipole-dipole interactions.

5. **Conclusion on Melting Points**:
- Because the intermolecular forces in covalent compounds are weak, less energy is required to overcome these forces. Thus, covalent compounds generally have low melting points compared to ionic compounds.

6. **Final Answer**:
- Covalent compounds have low melting points because they are held together by weak Van der Waals forces.