AP BIOLOGY

Detailed explanation-1: -Carbon dioxide can dissolve in water and then reacts with water to form carbonic acid. Since the acid then dissociates into carbonate ions and hydrogen ions and eventually forms H30+ ions, it follows that an increase in CO2 will cause a decrease in pH because the solution is getting more acidic.

Detailed explanation-2: -As mentioned, when carbon dioxide is dissolved in water, the release of hydrogen ions in carbonic acid is what lowers the pH. As CO2 levels increase around Earth, the amount of dissolved CO2 also increases, which increases the amount of carbonic acid, therefore decreasing the pH.

Detailed explanation-3: -Carbon dioxide influences the pH of blood by reacting with water to form carbonic acid (H2CO3), which can dissociate to form a hydrogen ion (H+) and a hydrogen carbonate ion (HCO3-). Increasing the concentration of carbon dioxide in the blood therefore results in more H+ ions and a lower pH.

Detailed explanation-4: -Carbonation is the mixing of water with the atmospheric carbon-dioxide to form carbonic acid. Rainwater reacts with carbon dioxide in the atmosphere to form carbonic acid. This reacts with calcium carbonate present in rocks like limestone to form a solution.

Detailed explanation-5: -For example, an increase in CO2 will result in increased carbonic acid formation (H2CO3) which leads to an increase in both HCO3-and H+ (pH).