Hemoglobin has maximum affinity for

Options

A. CO
B. `CO_2`
C. `O_2`
D. `NH_3`

Answer

**Step-by-Step Solution:**

1. **Understanding Hemoglobin's Function:**
Hemoglobin is a protein found in red blood cells that is responsible for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide from the body back to the lungs.

2. **Identifying the Options:**
The question provides four options regarding what hemoglobin has maximum affinity for:
- Option 1: Carbon monoxide (CO)
- Option 2: Carbon dioxide (CO2)
- Option 3: Oxygen (O2)
- Option 4: Anisine (ammonia)

3. **Analyzing Hemoglobin's Affinity:**
- Hemoglobin binds with oxygen to form oxyhemoglobin, which is essential for oxygen transport.
- It can also bind with carbon dioxide to form carbaminohemoglobin.
- However, hemoglobin has a significantly higher affinity for carbon monoxide than for oxygen or carbon dioxide. When hemoglobin binds with carbon monoxide, it forms carboxyhemoglobin, which is a stable complex.

4. **Conclusion:**
Based on the analysis, hemoglobin has the maximum affinity for carbon monoxide (CO). Therefore, the correct answer is **Option 1: Carbon monoxide (CO)**.

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