Name two salt that contain water of crystallisaton write their formula also
Answers
Answer:
zinc sulphate and copper sulphate
Activity : Take some crystals of blue vitriol in two test tubes. Add some water in one test tube and shake it.
What did you see?
What is the colour of the solution formed?
Heat the other test tube on low flame of a burner. What did you see?
What change did occur in the colour of blue vitriol?
What did you see in the upper part of the test tube?
When the second test tube cools down add some water in it and shake. What is the colour of the resulting solution? What inference can be drawn from this observation?
On heating, the crystalline structure of blue vitriol broke down to form a colourless powder and water came out. This water was part of the crystal structure of blue vitriol. It is called water of crystallisation. On adding water to the white powder a solution was formed which had the same colour as the solution in the first test tube. From this we come to know that no chemical change has occurred in the crystals of blue vitriol due to heating. Losing water on heating blue vitriol, breaking down of the crystal structure, losing blue colour and regaining blue colour on adding water are all physical changes.
