Sodium arsenite

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Sodium arsenite is a chemical compound with the formula NaAsO₂. It is the sodium salt of arsenous acid and is commonly used in various industrial and agricultural applications. Sodium arsenite is highly toxic and is classified as a carcinogen.

Chemical Properties

Sodium arsenite is a white, crystalline solid that is highly soluble in water. It has a molecular weight of 129.91 g/mol. The compound is typically found in the form of a trihydrate, NaAsO₂·3H₂O. In aqueous solution, sodium arsenite dissociates into sodium (Na⁺) and arsenite (AsO₂⁻) ions.

Production

Sodium arsenite is produced by the reaction of arsenic trioxide (As₂O₃) with sodium hydroxide (NaOH). The chemical equation for this reaction is: 2 NaOH + As₂O₃ → 2 NaAsO₂ + H₂O

Uses

Sodium arsenite has several applications, including:

• Pesticides: It has been used as an insecticide and herbicide, although its use has declined due to its toxicity.
• Wood Preservation: It is used in the preservation of wood to protect against insects and fungi.
• Laboratory Reagent: Sodium arsenite is used in various chemical reactions and as a reagent in laboratories.

Health Effects

Exposure to sodium arsenite can have severe health effects. It is highly toxic and can cause acute and chronic poisoning. Symptoms of acute poisoning include nausea, vomiting, abdominal pain, and diarrhea. Chronic exposure can lead to skin lesions, peripheral neuropathy, and an increased risk of cancer.

Safety Measures

Due to its toxicity, handling sodium arsenite requires strict safety measures. Personal protective equipment (PPE) such as gloves, goggles, and lab coats should be worn. It should be handled in a well-ventilated area, and any spills should be cleaned up immediately using appropriate procedures.

Regulation

The use of sodium arsenite is regulated in many countries due to its toxicity and environmental impact. It is classified as a hazardous substance and is subject to strict controls to prevent exposure and environmental contamination.

See Also

• Arsenic
• Arsenic poisoning
• Arsenous acid
• Sodium hydroxide
• Pesticide