Fear or excitement, generally cause one to breathe rapidly and it results in the decrease of concentration of `CO_(2)` in blood. In what way it will change pH of blood ?

Options

A. `pH` will increase
B. `pH` will decrease
C. No change
D. `pH` will adjust to `7`

Explanation

To answer the question regarding how a decrease in the concentration of CO2 in the blood affects the pH, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the Role of CO2 in Blood pH**:
- Carbon dioxide (CO2) is produced as a byproduct of metabolism and is transported in the blood. It plays a crucial role in the acid-base balance of the blood.
- CO2 reacts with water (H2O) to form carbonic acid (H2CO3), which can dissociate into bicarbonate (HCO3-) and hydrogen ions (H+). This reaction is reversible and is part of the bicarbonate buffer system.

2. **Effect of Rapid Breathing**:
- During rapid breathing (hyperventilation), the concentration of CO2 in the blood decreases because more CO2 is being exhaled than produced.
- A decrease in CO2 leads to a decrease in carbonic acid (H2CO3) formation, which in turn results in a decrease in hydrogen ion concentration (H+).

3. **Impact on pH**:
- The pH of a solution is inversely related to the concentration of hydrogen ions (H+). As the concentration of H+ decreases, the pH of the blood increases (becomes more alkaline).
- However, the blood has a buffering system that helps resist changes in pH.

4. **Buffering System in Blood**:
- The primary buffering system in blood is the bicarbonate buffer system, which consists of carbonic acid (H2CO3) and bicarbonate ions (HCO3-).
- This buffer system helps maintain the pH of blood around 7.4, despite fluctuations in CO2 levels.

5. **Conclusion**:
- Although a decrease in CO2 concentration can lead to an increase in pH (making it more alkaline), the buffering capacity of the blood prevents significant changes in pH.
- Therefore, the overall effect of decreased CO2 concentration due to rapid breathing is minimal, and the pH of the blood remains relatively stable.

### Final Answer:
The pH of the blood will not change significantly due to the buffering system present in the blood, despite a decrease in CO2 concentration.

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