Sodium pyrosulfite 7681-57-5 is white or slightly yellowish powder

Details:

Sodium pyrosulfite 7681-57-4 is white or slightly yellowish powder

English name:     Sodium Metabisulfite/cas:7681-57-4

molecule formula:Na2S2O5 
molecule weight:190.10
Physical properties:
It is white or tiny yellow crystal powder. Its relative density is 1.4. The solubility  is 54g/100mlwater at 20°C or 81.7g/100mlwater at 100°C,and the solution show acidity. It can solute in glycerine and little in alcohol. When exposed in air, it will oxidized into sodium sulfate, and can react with strong acid into sulfur dioxide gas and the salts. It is  deliquescent, and will decompose when heated to 150°C.

state santandard:GB1893-86
Index

Application:

Used in medicine when producing chloroform,solasulfone and methnylal;used as coagulant in rubber industry; used as dechlorided agent or assistants in printing and dyeing industry; used to improve leather properties in leather industry; used as developing agent in photosensitivity industry; used when producing hydroxyl geranial, hydrochloric hydroxylamine in chemical industry; used as bleaching agent, antiseptics,  antioxidant, ect.in food industry.

Sodium metabisulfite is a white or yellow crystalline powder or a small crystal with a strong SO2 odor. The specific gravity is 1.4. It dissolves in water and the aqueous solution is acidic. When it comes into contact with strong acid, SO2 is released and the corresponding salt is generated. If it is left in the air for a long time, it is oxidized. As Na2S2O6, so the product can not exist for a long time. Above 150 degrees Celsius, SO2 is decomposed.

Synonyms: disodiummetabisulfite; disodiumpyrosulphite; fertisilo; metabisulfitedesodium; Sodiummetabisufite; sodiummetabisulfite(na2-s2o5); sodiumpyrosulfite(na2s2o5); Sodium dissulfite; Sodium disulphite; Sodium pyrosulphite

application: Antioxidant, water treatment, preservative, decolorizer, reducing agent, rubber coagulator, mineral separation, developing agent, sewage treating agent