Carbonic acid in the context of "Phosgene"

Ocean acidification is the ongoing decrease in the pH of the Earth's ocean. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Carbon dioxide emissions from human activities are the primary cause of ocean acidification, with atmospheric carbon dioxide (CO₂) levels exceeding 422 ppm (as of 2024). CO₂ from the atmosphere is absorbed by the oceans. This chemical reaction produces carbonic acid (H₂CO₃) which dissociates into a bicarbonate ion (HCO−3) and a hydrogen ion (H). The presence of free hydrogen ions (H) lowers the pH of the ocean, increasing acidity (this does not mean that seawater is acidic yet; it is still alkaline, with a pH higher than 8). Marine calcifying organisms, such as mollusks and corals, are especially vulnerable because they rely on calcium carbonate to build shells and skeletons.

A change in pH by 0.1 represents a 26% increase in hydrogen ion concentration in the world's oceans (the pH scale is logarithmic, so a change of one in pH units is equivalent to a tenfold change in hydrogen ion concentration). Sea-surface pH and carbonate saturation states vary depending on ocean depth and location. Colder and higher latitude waters are capable of absorbing more CO₂. This can cause acidity to rise, lowering the pH and carbonate saturation levels in these areas. There are several other factors that influence the atmosphere-ocean CO₂ exchange, and thus local ocean acidification. These include ocean currents and upwelling zones, proximity to large continental rivers, sea ice coverage, and atmospheric exchange with nitrogen and sulfur from fossil fuel burning and agriculture.

Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula CO(NH₂)₂. This amide has two amino groups (−NH₂) joined by a carbonyl functional group (−C(=O)−). It is thus the simplest amide of carbamic acid.

In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula HCO−3.

Bicarbonate serves a crucial biochemical role in the physiological pH buffering system.

A carbonate is a salt of carbonic acid, (H₂CO₃), characterized by the presence of the carbonate ion, a polyatomic ion with the formula CO2−3. The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group O=C(−O−)₂.

The term is also used as a verb, to describe carbonation: the process of raising the concentrations of carbonate and bicarbonate ions in water to produce carbonated water and other carbonated beverages – either by the addition of carbon dioxide gas under pressure or by dissolving carbonate or bicarbonate salts into the water.

Ammonium carbonate is a chemical compound with the chemical formula [NH₄]₂CO₃. It is an ammonium salt of carbonic acid. It is composed of ammonium cations [NH₄] and carbonate anions CO2−3. Since ammonium carbonate readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a leavening agent and also as smelling salt. It is also known as baker's ammonia and is a predecessor to the more modern leavening agents baking soda and baking powder. It is a component of what was formerly known as sal volatile and salt of hartshorn, and produces a pungent smell when baked. It comes in the form of a white powder or block, with a molar mass of 96.09 g/mol and a density of 1.50 g/cm. It is a strong electrolyte.

Potassium carbonate is the inorganic compound with the formula K₂CO₃. It is a white salt, which is soluble in water and forms a strongly alkaline solution. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is used in production of dutch process cocoa powder, production of soap and production of glass. Commonly, it can be found as the result of leakage of alkaline batteries. Potassium carbonate is a potassium salt of carbonic acid. This salt consists of potassium cations K and carbonate anions CO2−3, and is therefore an alkali metal carbonate.

Chloroformic acid is a chemical compound with the formula ClCO₂H. It is the single acyl-halide derivative of carbonic acid (phosgene is the double acyl-halide derivative). Chloroformic acid is also structurally related to formic acid, in a way that the non-acidic hydrogen of formic acid is replaced by chlorine. Despite the similar name, it is very different from chloroform. It is described as unstable, decomposing into carbon dioxide and hydrogen chloride.

Chloroformic acid itself is too unstable to be handled for chemical reactions. However, many esters of this carboxylic acid are stable and these chloroformates are important reagents in organic chemistry. They are used to prepare mixed carboxylic acid anhydrides used in peptide synthesis.Important chloroformate esters include 4-nitrophenyl chloroformate, fluorenylmethyloxycarbonylchloride, benzyl chloroformate and ethyl chloroformate.