Molecular formula: Na2S2O3 5H2O
This is Sodium thiosulphate supplied in very strong HDPE bottle.
To dechlorinate tap water for aquariums or treat effluent from waste water treatments prior to release into rivers. The reduction reaction is analogous to the iodine reduction reaction. Treatment of tap water requires between 0.1 grams and 0.3 grams(depence chlorinate level in tap water) of pentahydrated sodium thiosulphate crystalline per 10 liters of water.
To lower chlorine levels in swimming pools and spas following super chlorination
To remove iodine stains, e.g. after the explosion of nitrogen triiodide.
Similarly, sodium thiosulfate reacts with bromine to render harmless products. Solutions of sodium thiosulfate are commonly used as a precaution in chemistry laboratories when working with bromine.
In bacteriological water assessment.
In the tanning of leather.
As a component in hand warmers and other chemical heating pads that produce heat by exothermic crystallization of a supercooled solution.
In pH testing of bleach substances. The universal indicator and any other liquid pH indicators are destroyed by bleach, rendering them useless for testing the pH. If one first adds sodium thiosulfate to such solutions, it will neutralize the color-removing effects of bleach and allow one to test the pH of bleach solutions with liquid indicators. The relevant reaction is akin to the iodine reaction: thiosulfate reduces the hypochlorite (active ingredient in bleach) and in so doing becomes oxidized to sulfate.