General Description
Colorless solid, transparent, colorless crystals. Used as a reagent for alkaloids and as an oxidizing agent. Isotope is used in labeling radiopharmaceuticals.
Reactivity Profile
SELENIOUS ACID decomposes when heated to toxic and volatile selenium dioxide. Serves as an oxidizing agent. Reacts exothermically with many reducing agents including hydroiodic acid, sulfurous acid, sodium hyposulfite, hydroxylamine salts, hydrazine salts, hypophosphorous acid, phosphorous acid [Merck]. Oxidizes many organic substances. Is oxidized to selenic acid by strong oxidizing agents.
Hazard
Toxic by inhalation, ingestion, and skin
absorption.
Health Hazard
Selenious acid and its salts are capable of penetrating the skin and can produce acute poisonings. Causes irritations and burns of the skin. It is highly toxic orally. Inorganic selenium compounds may cause dermatitis.
Potential Exposure
Selenious acid is used as a reagent for alkaloids and as an oxidizing agent. Isotope is used in labeling radiopharmaceuticals.
Fire Hazard
When heated to decomposition SELENIOUS ACID emits toxic fumes of selenium. Avoid heating.
First aid
Move victim to fresh air. Call 911 or emergency medical service. Give artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; give artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. Medical observation is recommended for 24 to 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a drug or other inhalation therapy
Shipping
UN3283Selenium compound, solid, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous material, Technical Name Required. UN3440 Selenium compound, liquid, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous material, Technical Name Required.
Incompatibilities
A strong oxidizer. Reacts exothermically with many reducing agents including hydroiodic acid, sulfurous acid, sodium hyposulfite, hydroxylamine salts, hydrazine salts, hypophosphorous acid, phosphorous acid. Incompatible combustibles, organic material, oxidizable materials, strong acids, strong bases. Contact with acids produce toxic and gaseous hydrogen selenide. Attacks metals.
Chemical Properties
Selenious acid is a colorless, crystalline solid.
Chemical Properties
White solid
Waste Disposal
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal.
Uses
As a reagent for alkaloids; as oxidizing agent.
Uses
As an oxidizing agent, as a reagent for alkaloidsSelenous acid is used in steel guns, wherein it changes the color of the steel from silver-grey to blue-grey. It serves as an important component of the Mecke reagent, which is utilized for drug testing. It acts as a source of selenium. It acts as a reagent for alkaloids and an oxidizing agent. Further, it is used in labeling radiopharmaceuticals. It is involved in the organic synthesis for the preparation of glyoxal.
Definition
ChEBI: Selenous acid is a selenium oxoacid. It is a conjugate acid of a hydrogenselenite.
Purification Methods
Recrystallise the acid from water. On heating it loses water and SeO2 sublimes. [Waitkins & Clark Chem Rev 36 235 1945.]
