What is the chemical formula for thiosulfate?

Thiosulfate is an anion that is composed of sulfur and oxygen, specifically featuring two sulfur atoms and three oxygen atoms. The chemical formula is represented as S2O3, with a charge of -2 for the entire anion, which indicates that it carries a negative charge due to the presence of extra electrons. This is why it is denoted as S2O3(2-).

The other choices pertain to different chemical species:

• The formula MnO4(-) represents the permanganate ion, which has one manganese atom and four oxygen atoms with a -1 charge.

• The formula PO4(3-) is for the phosphate ion, composed of one phosphorus atom and four oxygen atoms, carrying a -3 charge.

• The formula C2H3O2(-) is for the acetate ion, which consists of two carbon atoms, three hydrogen atoms, and two oxygen atoms with a -1 charge.

These differing compositions and charges illustrate why the correct answer for thiosulfate is S2O3(2-).