Detection methods of sulfate ion, chloride ion, permanganate ion, lead ion and mercury ion

Sulfate: barium ion (BaCl2) and dilute hydrochloric acid are used. A small amount of barium chloride solution was added dropwise, and a phenomenon was observed, resulting in a white precipitate. Drop a few drops of dilute hydrochloric acid and observe the phenomenon after shaking. Precipitation does not disappear, it is sulfate, precipitation disappears, it may be carbonate or sulfite.

Chloride ion: Silver nitrate and nitric acid are used. AgCl precipitate is produced, and the precipitate does not disappear when HNO3 is added, so it contains chloride ions.

Permanganate: First, see if the solution is purple. If it is not purple, permanganate ions can be excluded. If it is purple, you can drop a few drops of dilute sulfuric acid and then drop enough ferrous sulfate solution. If the original purple color turns pale, it means that the original solution contains permanganate ions.

Other reducing substances can also be used.

ICP-AES atomic absorption spectrometry generally uses heavy metals such as lead and mercury, both of which can measure trace concentrations.

Lead was treated with sulfate to obtain white precipitate of PbSO4 _ 4 _ 4, which was blackened by heating to obtain PBS.

Thiocyanate is used in the determination of mercury, resulting in a characteristic white precipitate. (protein denaturation is not enough as a determination method)