Henry's Law

Henry's law states that, at a constant temperature, the amount of a given gas that dissolves in a given volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with the liquid. English chemist William Henry established the relationship experimentally in 1803, publishing his results in a paper to the Royal Society describing how the solubility of gases such as carbon dioxide in water varied with pressure. The law is commonly expressed as p equals kH times C, where p is the partial pressure of the gas above the liquid, C is the concentration of the dissolved gas in the liquid, and kH is the Henry's law constant, a value specific to each particular gas-liquid pairing and temperature; it holds well for dilute solutions of gases that do not react chemically with the solvent, but breaks down at high concentrations or where the dissolved gas reacts with the liquid. The law has wide practical application, including explaining the fizzing of carbonated beverages when opened to lower pressure, decompression sickness in divers as dissolved nitrogen comes out of solution during ascent, and the exchange of gases between the atmosphere and the oceans.