Applications
Sodium thiosulfate pentahydrate is used as an analytical reagent in laboratories. It is used in photographic processing and in gold extraction. Its alkylated derivative S-alkylthiosulfonates are called Bunte salts. It is involved in the preparation of thioglycolic acid. Furthermore, it is used to dechlorinate tap water, for removing free bromine from solution and to check pH of bleach solutions with liquid indicators. Other used include tanning of leather, as an active component in hand warmers, in chemical heating pads and as an anionic surfactant to aid in dispersion of pharmaceutical preparations.

Solubility
Soluble in water. Insoluble in alcohol.

Notes
Incompatible with sodium nitrate, acids, strong oxidizing agents, iodides, silver salts, mercury salts and lead.