What ion is bicarbonate exchanged for at the red blood cell to maintain electroneutrality?

Bicarbonate is exchanged for chloride ions at the red blood cell to maintain electroneutrality during the process known as the chloride shift or Hamburger phenomenon. When carbon dioxide (CO2) enters red blood cells, it combines with water to form carbonic acid, which quickly dissociates into bicarbonate and hydrogen ions. The increase in bicarbonate inside the red blood cell prompts the export of bicarbonate into the plasma, allowing chloride ions to enter the red blood cell to balance the charges. This exchange is crucial for maintaining pH and electrolyte balance in the blood. Therefore, the correct connection lies in the relationship between bicarbonate and chloride ions during gas exchange and transport within the circulatory system.