abstract:Starch is often used in chemistry as an indicator for redox titrations where triiodide is present. Starch forms a very dark blue-black complex with triiodide which can be made by mixing iodine with iodide (often from potassium iodide).
Conceal disturbingelements like iron, copper, leadwith hydrogen fluoride amine-EDTA, add the potassium iodide to separateiodine, and takestarchasindicator, titrate with sodium hyposulfite.