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What type of reaction is it when you add sulfuric acid to a solution of sodium thiosulfate? What are the products?
Question Date: 2006-05-15
Answer 1:

Sodium thiosulfate reacts with dilute sulfuric acid to yield sodium sulfate (aq), sulfur (solid), sulfur dioxide (gas) and water. The reactions are as follows:

1. Sodium thiosulfate in the solid form is pentahydrate, i.e. Na2S2O3 : 5H2O(s)
When dissolved in water, you get

Na2S2O3 : 5H2O 2Na+ (aq) + S2O32- (aq) + 5H2O(l)

2. Sulphuric acid dissolved in water is

H2SO4(l) 2H+ (aq) + SO42- (aq)

3. The thiosulfate anion reacts with the hydrogen ion (from sulfuric acid) to produce sulfur, sulfur dioxide and water:

S2O32- (aq) + 2H+ (aq) S(s) + SO2 (g) + H2O (l)

4. Hence the net reaction is

Na2S2O3 : 5H2O(s) + H2SO4 2Na + (aq) + SO4 2- (aq) + S(s) + SO2(g) + 6H2 O (l)

Here you have a good reference, where you can learn more about your question:sodium_thiosulfate

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