Which of the following favours dissociation of `HbO_2 ` ?

Options

A. higher pH
B. ow temperature
C. lower `pCO_2`
D. high `H^+`

Answer

To determine which of the following factors favors the dissociation of HbO₂ (oxyhemoglobin), we need to analyze the options provided in the context of the oxygen-hemoglobin dissociation curve.

### Step-by-Step Solution:

1. **Understanding Oxyhemoglobin Dissociation**:
- Oxyhemoglobin (HbO₂) is formed when hemoglobin binds to oxygen. The dissociation of HbO₂ refers to the release of oxygen from hemoglobin.

2. **Factors Influencing Dissociation**:
- The dissociation of HbO₂ is influenced by several factors, which can shift the oxygen-hemoglobin dissociation curve to the right. A rightward shift indicates a decrease in hemoglobin's affinity for oxygen, promoting dissociation.

3. **Analyzing the Options**:
- **Higher pH value**: A higher pH (more alkaline) typically increases hemoglobin's affinity for oxygen, thus favoring association rather than dissociation. This is incorrect.
- **Low temperature**: Lower temperatures increase hemoglobin's affinity for oxygen, favoring association. This is incorrect.
- **Lower pCO₂ (partial pressure of CO₂)**: A lower pCO₂ would also increase hemoglobin's affinity for oxygen, favoring association. This is incorrect.
- **Higher H⁺ ion concentration**: An increase in H⁺ ions (lower pH, more acidic conditions) decreases hemoglobin's affinity for oxygen, thus favoring dissociation. This is correct.

4. **Conclusion**:
- Among the given options, the factor that favors the dissociation of HbO₂ is **higher H⁺ ion concentration** (option D).

### Final Answer:
**Higher H⁺ ion concentration** (Option D) favors the dissociation of HbO₂.

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