Final answer:
The pH in the blood is lower after hypoventilating because the buildup of CO2 leads to a more acidic environment. Hyperventilating expels excessive CO2, decreasing hydrogen ions and raising blood pH to more alkaline levels.
Step-by-step explanation:
The pH is lower after hypoventilating compared to hyperventilating. During hypoventilation, carbon dioxide (CO2) levels in the blood increase due to reduced breathing. This CO2 reacts with water to form carbonic acid, increasing the concentration of hydrogen ions (H+) and thereby lowering the pH of the blood, making it more acidic. Conversely, hyperventilation leads to excessive expulsion of CO2, resulting in a decrease of hydrogen ion concentration and a subsequent rise in blood pH, making it more alkaline.
Hypercapnia, or elevated blood CO2 levels, can occur due to hypoventilation, leading to a lower pH. Situations such as respiratory impairment or the presence of depressant drugs can contribute to hypoventilation. On the other hand, hyperventilation can be caused by panic attacks, pain, or high body temperature, driving off CO2 and increasing blood pH.