In lungs there is definite exchange of ions between RBC and plasma. Removal of `CO_(2)` from blood involves

Options

A. Efflux of `Cl^(-)` ions from RBC
B. Influx of `Cl^(-)` ion into RBC
C. Influx of `HCO_(3)^(-)` ions into RBC
D. Efflux of `HCO_(3)^(-)` ions form RBC \

Answer

To answer the question regarding the removal of carbon dioxide (CO₂) from blood and the exchange of ions between red blood cells (RBC) and plasma, we can break down the process into the following steps:

### Step-by-Step Solution:

1. **Understanding Gas Exchange**:
- In the lungs, gas exchange occurs where oxygen (O₂) is taken up and carbon dioxide (CO₂) is released. This exchange is driven by differences in partial pressures of these gases.

2. **Role of Red Blood Cells (RBCs)**:
- RBCs transport oxygen from the lungs to tissues and carry carbon dioxide from tissues back to the lungs. The movement of CO₂ into the RBCs occurs due to a higher concentration of CO₂ in the tissues compared to the RBCs.

3. **Formation of Carbonic Acid**:
- Once CO₂ enters the RBC, it reacts with water (H₂O) in the presence of the enzyme carbonic anhydrase to form carbonic acid (H₂CO₃). This reaction is crucial for the transport of CO₂.

4. **Dissociation of Carbonic Acid**:
- Carbonic acid (H₂CO₃) dissociates into bicarbonate ions (HCO₃⁻) and hydrogen ions (H⁺). The reaction can be summarized as:
\[ \text{CO₂} + \text{H₂O} \xrightarrow{\text{carbonic anhydrase}} \text{H₂CO₃} \rightarrow \text{HCO₃⁻} + \text{H⁺} \]

5. **Ion Exchange**:
- The increase in H⁺ ions leads to a decrease in pH (making the blood more acidic). To maintain electrical neutrality in the RBC, chloride ions (Cl⁻) move into the RBC from the plasma. This process is known as the "Chloride Shift."

6. **Conclusion**:
- The removal of CO₂ from blood involves the influx of chloride ions (Cl⁻) into the RBCs to balance the negative charge created by the bicarbonate ions (HCO₃⁻) that leave the RBCs into the plasma.

### Final Answer:
The removal of CO₂ from blood involves the influx of chloride ions (Cl⁻) into the RBCs.

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