Question

Which would you expect to be more soluble in water, stronium thiosulfate or calcium thiosulfate? (Explain your reasoning)

Answer 1

calcium thiosulfate is more soluble in water,

All sulfates are soluble except strontiumsulfate and barium sulfate

Thiosulfate (S₂O₃^2-) is an oxyanion of sulfur produced by the reaction of sulfite ions with elemental sulfur in boiling water,

S(s) + SO₃^2-(aq) S₂O₃^-2(aq)

Thiosulfate occurs naturally in hot springs and geysers, and is produced by certain biochemical processes. In the body, thiosulfate converts small amounts of cyanide ion into harmless products and plays a role in the biosynthesis of cysteine, a sulfur-containing amino acid that locks proteins into their correct three-dimensional shapes. Thiosulfate is not found in large quantities in nature. Solutions of thiosulfate break down into sulfur, sulfites, and sulfates when exposed to acids, light, metal ions, and bacteria.

Thiosulfate is a reducing agent. It is routinely used as a titrant to determine concentrations of oxidants such as hypochlorite in bleach and dissolved oxygen in water. It instantly dechlorinates water, and is used to stop bleaching action in the paper-making industry. Thiosulfate forms water-soluble complexes with many metals, making it useful in photoprocessing (where it dissolves excess silver bromide on the surface of exposed film, preventing excessive darkening). Thiosulfate is also useful in the extraction of silver from silver ore, in leather manufacture, and as a mordant in the textile industry.