In this episode we explain the multifaceted role of haemoglobin in the physiological movement of carbon dioxide through the bloodstream. We highlight how this protein facilitates the formation of bicarbonate by acting as a buffer for hydrogen ions and enables the creation of carbamino compounds by binding directly to the gas. Central to the discussion is the Haldane effect, which describes how the oxygenation state of blood influences its total carbon dioxide capacity. By contrasting gas exchange at the tissues and the lungs, the sources demonstrate how changes in chemical affinity ensure efficient respiratory waste removal. Furthermore, we provide evaluative feedback on common academic errors, emphasizing the need for quantitative precision and clear biochemical equations in medical examinations. This comprehensive overview serves as both a scientific guide and a pedagogical tool for understanding respiratory acid-base balance.