Covalent compounds have low m.p. because :

Options

A. Covalent molecules are held by weak van der Waals forces
B. Covalent bond is less exothermic
C. Covalent bond is weeker than ionic bond
D. Covalent molecules have definite shapes.

Explanation

To answer the question of why covalent compounds have low melting points, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding Covalent Bonds**:
- Covalent compounds are formed when two or more atoms share electrons. This sharing of electrons creates a covalent bond between the atoms.
- For example, in a hydrogen molecule (H₂), each hydrogen atom shares one electron with the other, forming a covalent bond.

2. **Structure of Covalent Compounds**:
- Covalent compounds typically exist as discrete molecules rather than as a continuous lattice structure (as seen in ionic compounds).
- The individual molecules are held together by intermolecular forces rather than strong ionic bonds.

3. **Intermolecular Forces**:
- The primary forces that hold covalent molecules together are known as Van der Waals forces (or London dispersion forces).
- These forces are relatively weak compared to ionic or covalent bonds that hold atoms together within a molecule.

4. **Effect on Melting Point**:
- Because the intermolecular forces (Van der Waals forces) in covalent compounds are weak, less energy (in the form of heat) is required to overcome these forces.
- As a result, covalent compounds tend to have lower melting points, allowing them to melt easily at lower temperatures.

5. **Conclusion**:
- Therefore, the low melting point of covalent compounds can be attributed to the weak Van der Waals forces of interaction between the molecules.

### Final Answer:
Covalent compounds have low melting points because they are held together by weak Van der Waals forces of interaction.