Read the following statement and select the correct one

Options

A. oxyhaemoglobin of erythrocytes is alkaline
B. In a healthy person the haemoglobin content is more than 25 g per 100 ml
C. In lungs the oxygen form the alveolus reaches the blood though active transport
D. The `H^(+)` released from carbonic acid combines with haemoglobin to form haemoglobinic acid

Answer

To solve the question, we need to analyze each of the four statements provided and determine which one is correct. Let's go through them step by step.

### Step 1: Evaluate the First Statement
The first statement claims that "the oxyhemoglobin of erythrocytes is basically alkaline."
- **Analysis**: Oxyhemoglobin is formed when oxygen binds to hemoglobin in red blood cells. It is known to be slightly acidic due to the presence of carbon dioxide in the blood which forms carbonic acid. Therefore, this statement is **false**.

### Step 2: Evaluate the Second Statement
The second statement states that "in a healthy person the hemoglobin content is more than 25 gm per 100 ml."
- **Analysis**: The normal hemoglobin content in a healthy adult is approximately 15 grams per deciliter (or 15 gm per 100 ml). Thus, this statement is also **false**.

### Step 3: Evaluate the Third Statement
The third statement mentions that "in lungs the oxygen from the alveolus reaches the blood through active transport."
- **Analysis**: Oxygen transfer from the alveoli into the blood occurs via diffusion, not active transport. It moves from an area of higher concentration (in the alveoli) to an area of lower concentration (in the blood). Therefore, this statement is **false**.

### Step 4: Evaluate the Fourth Statement
The fourth statement claims that "the H plus ions which are released from the carbonic acid combine with hemoglobin to form hemoglobinic acid."
- **Analysis**: When carbon dioxide enters the red blood cells, it combines with water to form carbonic acid, which dissociates into bicarbonate ions and hydrogen ions (H+). The H+ ions can bind to hemoglobin to form hemoglobinic acid. This statement is **true**.

### Conclusion
After evaluating all four statements, we find that the fourth statement is the only correct one.

### Final Answer
The correct statement is: "The H plus ions which are released from the carbonic acid combine with hemoglobin to form hemoglobinic acid."

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