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

Options

A. influx of `CI^(-)` ions into RBC
B. efflux of `CI^(-)` ions from RBC
C. influx of `Na^(+)` ions into RBC
D. efflux of ions from RBC

Answer

To solve 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 step by step:

### Step-by-Step Solution:

1. **Understanding CO₂ Transport**: Carbon dioxide is transported in the blood in three main forms: dissolved in plasma, as bicarbonate ions (HCO₃⁻), and bound to hemoglobin. The majority of CO₂ is converted to bicarbonate ions in the RBCs.

2. **Formation of Bicarbonate**: When CO₂ enters the RBC, it reacts with water to form carbonic acid (H₂CO₃) through the action of the enzyme carbonic anhydrase. This carbonic acid quickly dissociates into bicarbonate ions (HCO₃⁻) and hydrogen ions (H⁺).

3. **Chloride Shift**: To maintain electrical neutrality during the conversion of CO₂ to bicarbonate, chloride ions (Cl⁻) move into the RBC. This process is known as the "chloride shift" or "Hamburger phenomenon." As bicarbonate ions leave the RBC and enter the plasma, chloride ions enter the RBC from the plasma.

4. **Conclusion**: Therefore, the removal of CO₂ from the blood involves the influx of chloride ions into the RBC to balance the charge as bicarbonate ions are transported out into the plasma.

### Final Answer:
The correct answer to the question is: **Influx of chloride ions into the RBC.**

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