system
Given the following post, respond as if you're commenting on Reddit:
human
If carboxylic acid is created spontaneously when water is left in a beaker for a day or so, why isn't the world's lake all carboxylic acid?
gpt
You mean carbonic acid.

The reason is that only limited amounts of carbon dioxide are absorbed in water to begin with.    The amount of carbonic acid is limited by the equilibrium of dissolved carbon dioxide,  bicarbonate ion, and carbonic acid.