An allotrope of phosphorus which is poisonous in character is :
1) red P
2) black P
3) yellow P
4) white P

Options

A. red P
B. black P
C. yello P
D. violet P

Answer

To solve the question regarding which allotrope of phosphorus is poisonous in character, we can follow these steps:

### Step 1: Understand the Allotropes of Phosphorus
Phosphorus has several allotropes, but the main ones are:
- White Phosphorus (P4)
- Red Phosphorus
- Black Phosphorus

### Step 2: Analyze Each Allotrope
1. **White Phosphorus**:
- Exists as P4 molecules.
- It is a waxy solid and is known to be highly reactive and unstable.
- It is also known to be poisonous and can cause severe health issues upon exposure.

2. **Red Phosphorus**:
- It is more stable than white phosphorus and does not exhibit the same level of reactivity.
- It is not considered poisonous.

3. **Black Phosphorus**:
- This allotrope is the most stable form of phosphorus and is not poisonous.

4. **Yellow Phosphorus**:
- This term is often used interchangeably with white phosphorus, but it is not a recognized distinct allotrope in the same way as red and black phosphorus.

### Step 3: Identify the Poisonous Allotrope
From the analysis:
- White phosphorus is known for its poisonous characteristics due to its instability and high reactivity.

### Conclusion
The allotrope of phosphorus that is poisonous in character is **white phosphorus**.

### Final Answer
4) white P

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