Which one is not property of crystalline solid?

Options

A. Isotropic
B. Sharp melting point
C. A definite and regular geometry
D. High intermolecular forces

Explanation

To determine which option is not a property of crystalline solids, let's analyze each option step by step:

### Step 1: Understand the properties of crystalline solids
Crystalline solids have distinct properties that differentiate them from amorphous solids. Some key properties include:

1. **Sharp melting point**: Crystalline solids have a specific melting point at which they transition from solid to liquid.
2. **Defined and regular geometry**: The arrangement of particles in crystalline solids is orderly and repetitive, leading to a defined geometric shape.
3. **High intermolecular forces**: Crystalline solids often exhibit strong intermolecular forces, contributing to their rigidity and high melting points.
4. **Anisotropic nature**: Crystalline solids have different physical properties in different directions due to their ordered structure.

### Step 2: Analyze the options
Now, let's evaluate each option provided in the question:

- **Option 1: Isotropic** - This means that the properties of the material are the same in all directions. Crystalline solids are actually anisotropic, meaning their properties vary with direction.

- **Option 2: Sharp melting point** - This is a characteristic of crystalline solids, as they have a specific melting point.

- **Option 3: Defined and regular geometry** - This is also a property of crystalline solids due to their orderly arrangement of particles.

- **Option 4: High intermolecular forces** - Crystalline solids typically exhibit strong intermolecular forces.

### Step 3: Identify the incorrect property
From the analysis, we can see that:

- **Option 1 (Isotropic)** is not a property of crystalline solids, as they are anisotropic.

### Conclusion
Thus, the correct answer to the question "Which one is not a property of crystalline solid?" is **Option 1: Isotropic**.

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