7/29/2019 Copper Sulphate Penta Hydrate
1/2
Copper sulphate penta hydrate (CuSO4 5H2O)
Copper sulphate penta hydrate is known as blue vitirol and is
the mostcommon oxosalt of copper(2)PreparationCopper sulphate is
prepared industrially by blowing a current of air
through copper scrap and dilute sulphuric acid.
2Cu + 2H2O + O2 --------> 2CuSO4 + 2H2O
The crude copper(2) sulphate solution obtained contain iron(2)
sulphatesas impurity Dilute nitric acid is added to oxidize iron(2)
to iron(3) sulphatewhich remains in solution after crystallization
and CuSO4 5H2Ocrystallizes out.
The crystalline copper(2) sulphate, CuSO4 5H2O has the structure
inwhich four water molecules are coordinated to the central copper
cation insquare planar structure. The fifth water molecule is held
by hydrogenbonds between a sulphate anion and a coordinated water
molecule. Thefifth hydrogen bonded water molecule is deeply
embedded in the crystallattice and hence not easily removed.
Properties1. Copper sulphate penta hydrate is a blue coloured
crystalline solid,soluble in water.
2. Action of heat
On heating, copper sulphate penta hydrate gives trihydrate at
305 kelvin,monohydrate at 373 kelvin. On further heating it forms
white anhydrouscopper sulphate at 573 kelvin. The white anhydrous
copper sulphatedecomposes to give copper oxide and sulphur trioxide
on heating to 673kelvin.At 3o5 kelvin CuSO4 5H2O ---------> CuO
+ SO2At 373 kelvin CuSO4 3H2O ---------> CuO + SO2At 573 kelvin
CuSO4 H2O ---------> CuO + SO2At 673 kelvin CuSO4 --------->
CuO + SO2
3. Copper(2) sulphate forms well defined crystalline double
salts with
sulphates of strongly electropositive metals of the type
M2SO4.CuSO46H2O like (NH4)2SO4. CUSO4 6H2O. These double salts are
isomorphouswith the double salts of bivalent metals, Fe, Co,
Ni.
4. If an aqueous solution of copper(2)sulphate is saturated with
ammonia,the blue compound [Cu (NH3)4]SO4 H2O crystallizes on
evaporation.
Uses of CuSO4 5H20Copper(2)sulphate is used in copper plating
and electro refining of metals.It is used as a mordant in dyeing
and in electroplating. It is also used asgermicide and fungicide
under the name Bordeaux mixture which is amixture of CuSO4 and
Ca(OH)2.
