Allotropy is due to

Options

A. Difference in the number of atoms in the molecules in the crystal
B. difference in the preparation
C. Difference in physical properties
D. All of these

Answer

**Step-by-Step Text Solution:**

1. **Understanding Allotropy:**
- Allotropy refers to the existence of an element in more than one form in the same physical state. These different forms are known as allotropes. Allotropes of an element can have different physical properties but exhibit similar chemical properties.

2. **Examples of Allotropes:**
- A well-known example of allotropy is carbon, which has several allotropes including diamond and graphite. Diamond has a crystalline structure, while graphite has a layered structure. Additionally, carbon exists in amorphous forms such as coal, coke, and charcoal.

3. **Factors Contributing to Allotropy:**
- Allotropy can be attributed to several factors:
- **Difference in Number of Atoms in the Molecules:** The arrangement and bonding of atoms in the crystal lattice can differ, leading to distinct allotropes.
- **Difference in Preparation Methods:** The methods used to prepare different allotropes can vary significantly. For instance, diamond and graphite are formed under different conditions and processes.
- **Difference in Physical Properties:** Allotropes can exhibit different physical properties such as hardness, density, and electrical conductivity due to their structural differences.

4. **Conclusion:**
- Since all the mentioned factors contribute to the phenomenon of allotropy, the correct answer to the question "Allotropy is due to" is "all of this."

**Final Answer:**
Allotropy is due to all of the following factors: difference in number of atoms in the molecules in the crystal, difference in preparation, and difference in physical properties.

---