oksaalihapon

Oksaalihapon, widely known as oxalic acid or ethanedioic acid, is a colorless, crystalline dicarboxylic acid with the formula C2H2O4. It occurs naturally in many plants, including spinach, rhubarb, and notably oxalis (wood sorrel), and is produced on an industrial scale by oxidation of carbohydrates.

In water it dissociates in two steps, forming hydrogen oxalate (HC2O4−) and oxalate (C2O4^2−); typical pKa values are about 1.23 and 4.19, making it a relatively strong organic acid at low pH and a mild one at higher pH.

Oksaalihapon forms stable salts with many metal ions (oxalates). Insoluble calcium oxalate can precipitate, a concern in biological systems and stone formation. The acid is used in metal cleaning, wood and textile bleaching, and as a reagent in photography and analytical chemistry. It also serves as a reducing agent in certain reactions and as a buffering agent in specific pH ranges.

Safety and handling: oxalic acid is caustic and toxic if ingested; contact with skin or eyes can cause irritation; inhalation of dust should be avoided. It can form calcium oxalate crystals in tissues, including kidneys, so exposure must be minimized. In the environment, oxalate can be degraded by some microorganisms; high concentrations can affect aquatic life.

History: the name derives from Oxalis, the wood sorrel genus in which the compound was first identified. Today it is a common laboratory and industrial chemical, used under appropriate safety protocols.