Precipitation and reduction of thiosulfate with silver nitrate
silver nitrate solution, diluted Xi N R 34-50/53 S (1/2)-26-45-60-61
- One puts a spatula-tipful of sodium thiosulfate in the test tube and dissolves this with approx. 1 ml of water.
- Now one adds 2-3 drops of silver nitrate. A white sediment is precipitated which immediatly sinks and leaves behind a clear solution. The color of the sediment yellows and then quickly becomes black.
DisposalThe residues are to be disposed of as silver-containing waste.
At first poorly soluble silver thiosulfate is precipitated, this then reacts quickly with water to form black silver sulfide and sulphuric acid.
S2O32- + 2 Ag+ --> Ag2S2O3
Ag2S2O3 + H2O --> AgS + H2SO4
Precipitation of silver thiosulfate/sulfide
derived from experiment 3., "Nachweis mit AgNO3", p.126,