Which of the following is chemically inactive allotropic form of carbon ?

Options

A. (a) Coal
B. (b) Diamond
C. (c) Charcoal
D. (d) Animal charcoal

Answer

To determine which allotropic form of carbon is chemically inactive, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Allotropic Forms of Carbon**:
- Carbon has several allotropes, including coal, diamond, charcoal, and animal charcoal. Each of these has different physical and chemical properties.

2. **Define Chemically Inactive**:
- A chemically inactive substance does not readily react with acids or bases at room temperature. This means it remains stable and does not undergo chemical changes when exposed to these substances.

3. **Analyze Each Option**:
- **Coal**: This form of carbon can react with acids and bases, especially during combustion or chemical processing.
- **Diamond**: This is a crystalline form of carbon that is known for its hardness and stability. It does not react with acids or bases under normal conditions.
- **Charcoal**: This form of carbon is produced from the incomplete combustion of organic materials and can react with acids and bases.
- **Animal Charcoal**: Similar to charcoal, it can also react with acids and bases.

4. **Identify the Least Reactive**:
- Among the options, diamond is the only form that does not react with acids or bases at room temperature, making it the most chemically inactive allotropic form of carbon.

5. **Conclusion**:
- Therefore, the answer is **diamond** (Option B).

### Final Answer:
The chemically inactive allotropic form of carbon is **diamond** (Option B).