ABSTRACT
A quintessential feature of carbon dioxide is that it is the de-hydrated form of an acid, carbonic acid. Carbon dioxide could also be called the anhydrous form of carbonic acid. The very fact that carbon dioxide dissolves in water frustrated early attempts to study the gas, a gas known since the time of Joseph Black a quarter of a millennium ago as “fixed air.” Steven Hales was involved early on in the studies of carbon dioxide using his own clever device for collecting gases over water. The pH of ocean water near the surface is almost always found to be between 8.1 and 8.3, less acid than pure, neutral water. The solubility of carbon dioxide in ice is much smaller than in liquid water under ordinary circumstances. At ocean pH, though, because of the prevalent alkalinity, only a small fraction of the carbon dioxide species eludes reacting with water to form bicarbonate and carbonate.
