Mountain Dew is known for its lemon-lime taste and has a pH of 3.14, not the most acidic on the market. But the citric acid found in Mountain Dew, as well as citrus juices and fruits, is special.

or in the acidic clouds of Venus. But a different chemistry, which built all the requisite pieces out of different materials, might have a shot. Imagine cells that use methane, sulfuric acid, or ...