Photographic fixing agent. An emulsion of sodium thiosulfate (called hypo by photographers) is used to stop development of exposed film. Thiosulfate converts undeveloped silver bromide grains in the film into water-soluble silver thiosulfate complexes that can be removed when the film is washed.
S2O32- + AgBr(s) AgS2O3- + Br-
S2O32- + AgS2O3- Ag(S2O3)23-
CN- + S2O32- SCN- + SO32-This reaction is catalyzed by an enzyme produced by cell mitochondria to neutralize small quantities of ingested cyanide (which occurs naturally in cassava root, lima beans, and almonds!).
· In analytical chemistry, sodium thiosulphate is used for the determination of the strength of a given solution of iodine. · Sodium thiosulphate is preferred in iodometric analysis due to the fact that sodium thiosulphate is oxidized by iodine. It is also used to determine the strength of many oxidizing agents.
sodium thiosulphate
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The polyatomic anions in sodium sulphate have the formula SO4-2, while the polyatomic anions in sodium thiosulphate have the formula S2O3-2.
Sodium thiosulphate is a somewhat strong acid with pKas of 0.6 and 1.7 for the first and second dissociation respectively.
Hypo is used in photography it is a solution of Sodium thio sulphate, Na2S2O3
· In analytical chemistry, sodium thiosulphate is used for the determination of the strength of a given solution of iodine. · Sodium thiosulphate is preferred in iodometric analysis due to the fact that sodium thiosulphate is oxidized by iodine. It is also used to determine the strength of many oxidizing agents.
In iodometry sodium thiosulphate is used because it is standardized by potassium dichromate and it is the best and relaible way to standardized sodium thiosulphate using iodometric titration. Infact sodium thiosulphate is also standardized by iodimetry. The difference between both of them is only of iodine. In iodometry iodine gas is liberated that will further react with sodium thiosulphate but in iodimetry standard solution of iodine is used.
Because it used to be called Sodium hyposulphite.
Starch
To ensure the stability of the solution
sodium thiosulphate
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1.sodium benzoate
The polyatomic anions in sodium sulphate have the formula SO4-2, while the polyatomic anions in sodium thiosulphate have the formula S2O3-2.
Sodium thiosulfate is used against cyanide poisoning and pitiryazis.For nonmedical uses see this link.
Sodium thiosulphate is a somewhat strong acid with pKas of 0.6 and 1.7 for the first and second dissociation respectively.