Potassium hydrogenoxalate is a

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quanti ...

with formula KHC₂O₄ or K⁺·HO₂C-CO₂⁻. It is one of the most common salts of the

hydrogenoxalate Hydrogenoxalate or hydrogen oxalate is an anion with chemical formula or , derived from oxalic acid by the loss of a single proton; or, alternatively, from the oxalate anion by addition of a proton. The name is also used for any salt containing ...

anion, and can be obtained by reacting

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which expl ...

with

oxalic acid Oxalic acid is an organic acid with the systematic name ethanedioic acid and formula . It is the simplest dicarboxylic acid. It is a white crystalline solid that forms a colorless solution in water. Its name comes from the fact that early inve ...

in 1:1 mole ratio. The salt is also known as: potassium hydrogen oxalate, potassium bioxalate, acid potassium oxalate, or monobasic potassium oxalate. In older literature, it was also called: Salt of sorrel, (retrieved via Internet Archive) sorrel salt, ''sel d'oseille'', Salt of Sorrel labelled “sel d'oseille”. Old dark-amber glass vial marked “sel d'oseille” with protective leaden cap. ''sal acetosella''; or, ''inaccurately, salt of lemon'' (due to the similar acidic ''“lemony”'' taste of the edible ''common sorrel'' or ''garden sorrel''.) “This fresh, “lemony” sourness has been highly prized in cuisines all over the world.” Potassium hydrogenoxalate occurs in some plants, notably

sorrel Sorrel (''Rumex acetosa''), also called common sorrel or garden sorrel, is a perennial herbaceous plant in the family Polygonaceae. Other names for sorrel include spinach dock and narrow-leaved dock ('dock' being a common name for the genus '' ...

. It is a commercial product used in photography, marble grinding, and removing ink stains.

Properties

The

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and