Copper Sulphate (Blue Salt)

Additional Details

Copper(II) sulphate pentahydrate (CuSO4.5H2O), is a common salt of copper. Copper sulphate is a bright blue, odourless crystalline solid which is soluble in water. The archaic name for copper(II) sulphate is "blue vitriol" or "bluestone". It has numerous applications including as an ingredient in fungicides, algaecides, and pesticides; laboratory analytical reagent,for zinc etching and as a mordant.

Copper sulphate is a commonly included chemical in children's che­mistry sets and is often used in high school crystal growing and copper plating experiments. However due to its toxicity, it is not recommended for small children and should always be supervised.

Copper sulphate is often used to demonstrate an exothermic reaction, in which steel wool or magnesium ribbon is placed in an aqueous solution of CuSO4.

It is used in school chemistry courses to demonstrate the principle of mineral hydration. The pentahydrate form, which is blue, is heated, turning the copper sulfate into the anhydrous form which is white, while the water that was present in the pentahydrate form evaporates. When water is then added to the anhydrous compound, it turns back into the pentahydrate form, regaining its blue colour. It can be used to plate metals with copper.