Which of the following reacts rapidly with oxygen in the air at ordinary temperature? 

Options

A. White P
B. Red P
C. `N_(2)`
D. `CO_(2)`

Answer

To determine which of the given options reacts rapidly with oxygen in the air at ordinary temperature, we will analyze each option based on their ignition temperatures and reactivity with oxygen.

### Step-by-Step Solution:

1. **Understanding Ordinary Temperature**:
- Ordinary temperature is typically considered to be around 27 to 30 degrees Celsius.

2. **Analyzing Each Option**:
- **Option 1: White Phosphorus**:
- White phosphorus has an ignition temperature of about 30 degrees Celsius. This means it can ignite and react with oxygen at ordinary temperature. Therefore, it reacts rapidly with oxygen in the air at room temperature.

- **Option 2: Red Phosphorus**:
- Red phosphorus has a much higher ignition temperature of about 240 degrees Celsius. This indicates that it does not react rapidly with oxygen at ordinary temperature. Thus, it is not the correct answer.

- **Option 3: Nitrogen (N₂)**:
- Nitrogen is an inert gas and does not react with oxygen at ordinary temperatures. It does not support combustion, so it cannot be the correct answer.

- **Option 4: Carbon Dioxide (CO₂)**:
- Carbon dioxide is used as a fire extinguisher and does not react with oxygen at ordinary temperatures. Therefore, it is also not the correct answer.

3. **Conclusion**:
- Based on the analysis, the only substance that reacts rapidly with oxygen at ordinary temperature is **White Phosphorus**.

### Final Answer:
**White Phosphorus** reacts rapidly with oxygen in the air at ordinary temperature.

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