Copper sulphate or cuprous sulphate (Cu2SO4 is also referred to as blue vitriol or bluestone. It is used in most of the multivitamin and mineral supplements. There exists an ionic bond between the copper cation (Cu2+) and the sulphate anion (SO42-), in the compound of copper sulphate. Pentahydrate copper sulphate or pure copper sulphate(CuSO4.5H2O) is the most common form of the compound. Today the world consumption of the compound crosses over 300,000 tons per annum, and approximately a third is used in agriculture. Many industries have found the application of copper sulphate. The compound is used in a range of industries as well as agricultural purposes.
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The most common field to make extensive use of the product in the field of agriculture. Industries, however, have found its usage in dyeing and electroplating. It is used in the manufacture of some of the best fungicides in the market. But the overdose of copper can cause both acute chronic and liver injury. Many industries have found the application of copper sulphate. One such example is the synthetic fibre industry. It uses the compound for the production of their raw materials.
The metal industry also uses large quantities of copper sulphate. It acts as an electrolyte in copper refining and copper coating steel wire before wire drawing.
It also used the process of copper plating. The compound has also shown usage in the mining industry. It acts as an activator in the concentration by froth flotation of lead, gold, and cobalt ores. Other industries, like the printing industry, also have an increase in the usage of copper sulphate. It is used as an electrolyte in the production of electrotype and as an etching agent for engraving the print. It is also used in anti-fouling paints and plays an important role in glass colouring. It is safe to say that the compound has found its usage in almost all existing industries.
In the process of manufacturing copper sulphate, virgin copper has been used as a starting raw material. One of the biggest productions comes from nonferrous scrap. It is refined, and then the molten metal is poured into water. It produces rough spherical porous pieces about the size of marbles, which are termed as "shot." The shots are then dissolved in dilute sulphuric acid. It is done in the presence of air to produce hot saturated liquor.
The liquor produced is then allowed to cool in a way that compensates for the requirements. If we aim for traditional large crystals of copper sulphate, the liquor is allowed to cool slowly in large cooling vats. The vats have strips of lead and provide a surface for the crystals to grow on. However, if the targeted product is granulated (snow) crystal copper sulphate, then the cooling process is accelerated using water-cooled vessels.
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The molar mass of the compound differs following its forms. The anhydrous form of copper sulphate is around 169.609 grams per mole. At the same time, the pentahydrate form is around 249.685 grams per mole. The appearance of the anhydrous copper sulphate is a grey-white powder, but the pentahydrate, on the other hand, comes in bright blue colour. Both of the compound's forms also differ in density. The anhydrous has 3.6 grams per cubic centimetre of density, where the pentahydrate has around 2.286 g.cm-3 density.
1. Write a Note on the Physical State of Copper Sulphate
The compound is a blue solid, which is in the aqueous solution. Meaning the molecules of the compound are loosely bound to each other. It is whitish in appearance in its anhydrous form. It is when the compound is not bound to the molecule of water. In the hydrated state, however, the compound has five of the water molecules attached to it. Upon heating, the compound gets dissolved. The dissolving is true for both the anhydrous and the pentahydrate forms since they both decompose on heating. Hence, they cannot be said to have an exact boiling point.
2. What is the Difference Between Anhydrous White and Pentahydrate Blue?
Anhydrous copper sulphate is the purest form of copper sulphate and is white. The name itself suggests that it has no water in it. The compound is in the form of a dry solid due to the water molecules being trapped in its ionic lattice. It has a unique property that, upon the addition of water, the compound turns blue. Such colour change is used to determine the presence of water.
Pentahydrate copper sulphate is the hydrated form of the compound and emits blue colour. It does so due to a d-d transition in its structure, caused by the presence of water molecules.