Potassium arsenite is a white crystalline solid
Potassium metaarsenite is used in veterinary medicine; and for chronic dermatitis in man. Potassium arsenite reduces silver salt to metallic silver during mirror silvering. Currently, it is probably not being used for this purpose.
UN1678 Potassium arsenite (solid), Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
A weak base. Reacts with acids and decomposes on contact with strong acids producing acetic acid fumes. Arsine, a very deadly gas, can be released in the presence of acid or acid mist. Incompatible with alkaloidal salts, strong oxidizers; bromine azide, hypophosphites, sulfites in acid solution; iron salts; heavy metals and heavy metal compounds. Hydrogen gas can react with inorganic arsenic to form the highly toxic gas, arsine.