Which of the following properties of red P and white P are related to their structure?

Options

A. Large difference in melting point.
B. Difference in hardness.
C. Ignition behaviour.
D. None of these.

Answer

To determine which properties of red phosphorus (red P) and white phosphorus (white P) are related to their structure, we can analyze the differences in their physical properties and how these differences arise from their molecular structures.

### Step-by-Step Solution:

1. **Understanding the Structures**:
- **White Phosphorus**: It has a tetrahedral structure consisting of P4 molecules. This structure makes it less stable and more reactive.
- **Red Phosphorus**: It has a polymeric structure, which consists of long chains of phosphorus atoms. This structure is more stable and less reactive compared to white phosphorus.

2. **Melting Point**:
- **Observation**: There is a large difference in the melting points of red P and white P.
- **Explanation**: The tetrahedral P4 molecules in white phosphorus are held together by weak van der Waals forces, resulting in a lower melting point. In contrast, the polymeric structure of red phosphorus has stronger covalent bonds, leading to a higher melting point.

3. **Hardness**:
- **Observation**: Red phosphorus is harder than white phosphorus.
- **Explanation**: The polymeric structure of red phosphorus gives it a more rigid and solid form, whereas the molecular structure of white phosphorus is softer and more waxy due to its weaker intermolecular forces.

4. **Ignition Temperature**:
- **Observation**: The ignition temperatures of red P and white P are different.
- **Explanation**: The reactivity of white phosphorus is higher due to its molecular structure, which allows it to ignite at lower temperatures compared to the more stable red phosphorus.

### Conclusion:
Based on the analysis, the properties that are related to the structure of red phosphorus and white phosphorus are:
1. Large difference in melting point.
2. Difference in hardness.
3. Difference in ignition temperature.

### Final Answer:
The properties of red phosphorus and white phosphorus that are related to their structure are:
- Large difference in melting point.
- Difference in hardness.
- Difference in ignition temperature.