Does the removal of carbon dioxide decrease the pH of water?

Removing carbon dioxide from water generally leads to an increase in pH. This is because carbon dioxide, when dissolved in water, forms carbonic acid, which dissociates to release hydrogen ions (H+) that lower the pH, making the water more acidic. When carbon dioxide is removed, the concentration of carbonic acid decreases, resulting in fewer hydrogen ions being present, which allows the pH to rise.

In many scenarios—especially in natural waters where carbon dioxide levels can fluctuate—the removal of carbon dioxide tends to result in a shift toward higher pH values. Hence, the assertion that the removal of carbon dioxide decreases the pH of water is incorrect, and the answer is true that such removal increases pH levels. The context of other water chemistry factors may affect this behavior, but fundamentally, the relationship between carbon dioxide removal and pH is a straightforward chemical principle.