Oxalic acid also known as ethanedioic acid is a simple dicarboxylic acid with the structure (HOOC)-(COOH). It is one of the strongest acid among the organic acids. It is corrosive and toxic nature. It was first discovered in 1769 by the German pharmacist Johann Christian Wiegleb in the plant Oxalis acetosella, from which the name “oxalic acid” is derived. In the year 1776, Oxalic acid was prepared synthetically for the first time by Scheele. It is found unsurprisingly in varying concentrations, occurring in several plants such as tea, rhubarb, spinach, cocoa, nuts, berries and beans.
It is readily oxidized, this characteristic property makes it useful as a reducing agent for photography, bleaching, and ink removal. Oxalic acid is strong that it is widely applied industrially for bleaching and heavy-duty cleaning, notably for rust removal.
It is best known agent in wood bleaching. Oxalic acid is capable of cleaning wood from its gray colour due to continuous exposure to sun light. This can be done by rubbing oxalic acid on the affected wood can lighten its gray form. It is used to clean and sterilize home brewing utensils used to make beer and wine. It also used as a purifier in the pharmaceutical industry and also used by rock collectors to clean a variety of minerals and related specimens.
It is used to remove hard water stains from tile and plumbing fixtures. It is also used in removing of paint and varnishes, as an auto radiator cleanser and as a disinfectant to control bacteria and germs. It is used in commercial rust removers to eradicate rust stains from tubs, sinks and tile, as well as from metal. Oxalic acid is feasible option for beekeepers to control mites. In the field of mineral processing it is used as a precipitating agent. It is also used in the treatment of wastewater, because oxalic acid helps take away calcium from water.