One of the following statement incorrect

Options

A. Reduced haemoglobin is more acidic than oxygenated Hb
B. 100 ml of blood can carry 19.8 ml of oxygen
C. Every deciliter of blood releases in lungs 3.7 ml of `CO_(2)`
D. About 7 % of `CO_(2)` entering blood is converted `H_(2)CO_(3)`

Answer

To determine which statement is incorrect regarding the transport of gases in the blood, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Evaluate the First Statement**:
- The first statement claims that reduced hemoglobin is more acidic than oxygenated hemoglobin.
- This statement is **correct** because when hemoglobin binds with oxygen, it becomes oxyhemoglobin, which is less acidic compared to reduced hemoglobin.

**Hint**: Remember that the binding of oxygen to hemoglobin alters its acidity.

2. **Evaluate the Second Statement**:
- The second statement mentions that 100 ml of blood can carry 19.8 ml of oxygen.
- This statement is also **correct**. Under normal physiological conditions, blood can carry approximately 20 ml of oxygen per 100 ml of blood, and 19.8 ml is a reasonable approximation.

**Hint**: Consider the saturation level of hemoglobin and its capacity to transport oxygen.

3. **Evaluate the Third Statement**:
- The third statement asserts that 3.7 ml of CO2 is released from every deciliter of blood to the lungs.
- This statement is **correct** as well. While the exact value can vary, approximately 4 ml of CO2 is released from 100 ml of blood, making 3.7 ml a reasonable estimate.

**Hint**: Think about the general transport capacity of carbon dioxide in blood.

4. **Evaluate the Fourth Statement**:
- The final statement claims that 7% of carbon dioxide entering the blood is converted into H2CO3 (carbonic acid).
- This statement is **incorrect**. In reality, about 70% of CO2 is converted into bicarbonate ions, and only a small fraction (about 5-7%) is dissolved in plasma, while a larger portion is carried as bicarbonate ions.

**Hint**: Recall the different forms in which carbon dioxide is transported in the blood.

### Conclusion:
The incorrect statement is the one that claims 7% of carbon dioxide is converted into carbonic acid (H2CO3). The majority of CO2 is actually transported in the form of bicarbonate ions.

### Summary of Incorrect Statement:
- The statement regarding the percentage of CO2 converted to carbonic acid is inaccurate as it misrepresents the primary form of CO2 transport in the blood.