Prepare the saturated solution of Bazaar Copper Sulphate

Experiment 4: TO PREPARE THE SATURATED SOLUTION OF BAZAAR COPPER SULPHATE

OBJECTIVE

TO PREPARE THE SATURATED SOLUTION OF BAZAAR COPPER SULPHATE AND TO OBTAIN THE PURE CRYSTAL OF THE SAME SALT (BLUE VITRIOL) BY CRYSTALLIZATION

APPARATUS REQUIRED

1. Beaker
2. Glass rod
3. Burner
4. Filter paper
5. Test tube
6. Tripod Stand
7. Porcelain basin

CHEMICAL REQUIRED

Impure Bazaar Copper Sulphate

THEORY

A crystal is a piece of a crystalline solid that has a geometrical shape of having a regular pattern in the arrangement of its constituent particles. When a saturated solution of a salt prepared at laboratory temperature is heated up to a crystalization point followed by cooling, results in the formation of crystals. So the process of obtaining crystal by evaporating the saturated solution followed by cooling is called crystallization. During crystallization, all the impurities remain in the mother liquor Hence, the crystals thus obtained are in the pure state.

During crystallization, the crystallization point should be detected precisely otherwise overheating may lead to loss of one or more water of crystallization.

\underset{Blue\ vitriol}{CuSO_{4}.5H_{2}O}\overset{\triangle}{\rightarrow} CuSO_{4}+5H_{2}O

PROCEDURE

One test tube of water was taken in a clean beaker and impure copper sulphate was added to the beater to get a saturated solution at room temperature and filtered with constant stirring with a glass rod.

Then, the saturated solution was taken in a porcelain basin and evaporated up to the crystallization point (C.P). (To confirm the CP, a drop of solution is taken with a glass rod and made in contact with the outer surface of the test tube filled with cold water. The appearance of milli-crystals showed reaching of CP) After reaching that point, the basin was removed from the flame and allowed to cool slowly at room temperature, basin was floated in a water trough containing cold water. After some time, there was the formation of the crystal. Crystals were separated from the liquid by decantation of mother liquor and soaked between pieces of filter paper.

OBSERVATION TABLE

RESULT

Pure and dry crystals of copper sulphate were obtained from the impure sample.

CONCLUSION

We can obtain the pure crystal of copper sulphate (blue vitriol) from the mixture of saturated solution through crystallisation.

PRECAUTIONS

1. Saturated solution of copper sulphate should be prepared at room/lab temperature.
2. The solution should be evaporated up to the crystallization point.
3. The solution should not be evaporated completely.
4. Blue vitriol should not be dried in an open flame