Final answer:
As acidity increases, the affinity of hemoglobin for the oxygen it carries decreases.
Step-by-step explanation:
As the level of carbon dioxide in the blood increases, more hydrogen ions (H*) are produced and the pH decreases. This decrease in pH reduces the affinity of hemoglobin for oxygen, causing the oxygen to dissociate from the hemoglobin molecule. As a result, the oxygen dissociation curve shifts to the right, indicating a decrease in affinity for oxygen. Therefore, as acidity increases, the affinity of hemoglobin for the oxygen it carries decreases.