Bone black is a polymorphic form of

Options

A. Phosphorus
B. Sulphur
C. Carbon
D. Nitrogen

Explanation

**Step-by-Step Solution:**

1. **Understanding Bone Black**: Bone black, also known as bone char or animal charcoal, is a black powder made from carbonized animal bones. It is primarily used as a pigment and in filtration processes.

2. **Identifying the Element**: To determine the polymorphic form of bone black, we need to identify the element that it is associated with. Bone black is derived from animal bones, which primarily consist of calcium phosphate and organic materials.

3. **Polymorphism Concept**: Polymorphism refers to the ability of a substance to exist in more than one form or crystal structure. In the case of bone black, we need to find out which element it is a polymorphic form of.

4. **Allotropes of Phosphorus**: Phosphorus is known to have several allotropes, including white phosphorus, red phosphorus, and black phosphorus. Bone black is related to phosphorus.

5. **Conclusion**: Bone black is a polymorphic form of phosphorus, specifically an amorphous form of phosphorus.

**Final Answer**: Bone black is a polymorphic form of phosphorus.

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