What is sodium thiosulfate used for? How does sodium thiosulfate work in photography? What are the medical uses? How is sodium thiosulfate used in gold mining

Na₂S₂O₃ 

Sodium thiosulfate, also known by its chemical formula Na2S2O3, is a versatile inorganic compound that has several important uses in various industries and applications. Here's an overview of what sodium thiosulfate is and its common uses:

Chemical Composition: Sodium thiosulfate is composed of sodium ions (Na+), thiosulfate ions (S2O3^2-), and water molecules (H2O) in its hydrated form.

Photography: One of the primary uses of sodium thiosulfate is in photography as a photographic fixer or hypo. It is used to fix photographic images by removing unexposed silver halide from photographic emulsions. This process makes the image permanent and prevents further exposure to light from affecting it.

Water Treatment: Sodium thiosulfate is employed in water treatment processes, particularly in dechlorination. It can neutralize and remove chlorine and chloramines from water, making it safe for various industrial and environmental applications.

Medical Applications: In some medical situations, sodium thiosulfate is used as an antidote to treat cyanide poisoning. It works by converting cyanide into a less toxic compound, thiocyanate, which can be excreted from the body.

Analytical Chemistry: Sodium thiosulfate is used in analytical chemistry as a titrant in redox titrations. It can be used to determine the concentration of certain substances, including iodine, by reacting with them in a controlled chemical reaction.

Gold Extraction: In gold mining, sodium thiosulfate is sometimes used as an alternative to cyanide for extracting gold from ores. This is considered a more environmentally friendly method, as it generates fewer toxic byproducts.

Textile Industry: Sodium thiosulfate is used in the textile industry for removing excess chlorine after bleaching processes, which helps prevent damage to fabrics.

Disinfection: In some cases, sodium thiosulfate is used for disinfection and sanitation purposes due to its ability to neutralize chlorine and chloramine disinfectants in water.

Chemical Synthesis: It is also used in various chemical reactions and synthesis processes, such as in the production of sulfur dyes, in certain photographic developers, and as a reducing agent in chemical reactions.

Sodium thiosulfate is a compound with a wide range of applications, primarily owing to its ability to react with and neutralize chlorine compounds and its redox properties in chemical reactions. Its uses span across industries including photography, water treatment, medicine, and chemical manufacturing.

Molar Mass: 248.18 g/mol
Form:  efflorescent monoclinic crystalline substance

CAS Number: 7772-98-7
EC Number: 231-867-5
Density: 1.667 g/cm³
Synonyms: SODIUM THIOSULFATE, Sodium thiosulphate, Disodium thiosulfate, sodiumthiosulfate, Sodothiol, Hypo, Chlorine Control, Chlorine Cure, Declor-It, Sodothiol; Sulfactol; Sulfothiorine, sulfothiorine, Antichlor