Sodium oxalate

Sodium oxalate, also known as disodium oxalate, is an organic compound with the formula Na2C2O4. It is a white, crystalline, odorless solid that forms a monohydrate, Na2C2O4·H2O. Sodium oxalate is a salt of oxalic acid, a dicarboxylic acid that occurs naturally in many plants and vegetables. It is used in various industrial processes, including the manufacture of certain dyes and bleaching agents, as well as in laboratories for the standardization of potassium permanganate solutions.

Properties

Sodium oxalate is soluble in water, with its solubility decreasing with the increase in temperature. It is practically insoluble in ethanol. When heated, it decomposes to form sodium carbonate, carbon monoxide, and carbon dioxide. This compound acts as a reducing agent in chemical reactions and can form coordination compounds with transition metals.

Production

Sodium oxalate can be produced by neutralizing oxalic acid with sodium hydroxide (NaOH) in a controlled environment. The reaction yields sodium oxalate and water. Industrially, it can also be generated as a byproduct in the processing of titanium dioxide.

Uses

In the laboratory, sodium oxalate is primarily used as a primary standard for standardizing potassium permanganate solutions, a common titrant in redox titrations. Its precise known concentration and stability make it suitable for this purpose. Additionally, it finds application in the preparation of metal oxalates for electroplating and in the textile industry as a mordant.

Health and Safety

Sodium oxalate is toxic if ingested, inhaled, or upon contact with skin. It can cause irritation to the skin, eyes, and respiratory system. Ingestion of sodium oxalate can lead to serious health issues, including renal failure, due to the formation of insoluble calcium oxalate crystals that can damage the kidneys. Safety measures include wearing protective clothing, gloves, and eye protection when handling the substance. In case of exposure, immediate medical attention is necessary.

Environmental Impact

The environmental impact of sodium oxalate is primarily associated with its potential to form insoluble oxalate salts with heavy metals, which can persist in the environment. Proper disposal methods should be employed to minimize its environmental footprint.