The sharp melting point of crystalline solids is due to :

Options

A. a regular arrangement of constituent particles observed over a short distance in the crystal lattice.
B. a regular arrangement of constituent particles observed over a long distance in the crystal lattice.
C. same arrangement of constituent particles in different directions.
D. different arrangement of constituent particles in different directions.

Explanation

**Step-by-Step Solution:**

1. **Understanding Crystalline Solids**: Crystalline solids are defined as substances whose constituent particles (atoms, ions, or molecules) are arranged in a highly ordered and repeating geometric pattern. This arrangement extends throughout the entire solid, giving it a long-range order.

2. **Properties of Crystalline Solids**: One of the key characteristics of crystalline solids is their sharp melting point. This means that they melt at a specific temperature, rather than over a range of temperatures.

3. **Reason for Sharp Melting Point**: The sharp melting point of crystalline solids is primarily due to the regular and uniform arrangement of the constituent particles in the crystal lattice. When heat is applied, the energy is uniformly distributed throughout the solid, allowing all the particles to overcome their intermolecular forces simultaneously at a specific temperature.

4. **Conclusion**: Therefore, the sharp melting point of crystalline solids is attributed to the long-range order and regular arrangement of particles within the crystal lattice.

**Final Answer**: The sharp melting point of crystalline solids is due to the regular arrangement of constituent particles observed over a long distance in the crystal lattice.

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