Name: Chemical Properties of Bases
Uploaded: 2019-07-19
Duration: 4 min 4 s
Description: You are already familiar with the physical properties of bases that they are bitter to taste and soapy to touch. Now explore the chemical properties of bases.

Question

Write the chemical formula of hydrated copper sulphate and anhydrous copper sulphate. Giving an activity illustrate how these two are interconvertible.

Accepted Answer

The chemical formula of hydrated copper sulphate is ${CuSO}_{4} \cdot 5 H_{2} O (s)$ and anhydrous copper sulphate is ${CuSO}_{4} (s)$ . Crystals of some salts contain certain amount of associated water. The water associated with the crystal (or molecule) of any salt is called water of crystallisation.

Activity:

Take a few crystals of hydrated copper sulphate in a dry boiling tube. These are blue in colour.

Heat the boiling tube by holding it with a test tube holder on the flame of the burner.

Observations: You will observe that the colour of copper sulphate crystals after heating becomes white. You may also notice water droplets on the mouth side of the boiling tube which are obtained from water of crystallisation.
After adding 2-3 drops of water on the white sample of copper sulphate (obtained after heating) you will observe that the blue colour of copper sulphate crystals is restored.
$\underset{(Blue)}{{CuSO}_{4} \cdot 5 H_{2} O} \overset{∆}{\to} \underset{(White)}{{CuSO}_{4}} + 5 H_{2} O \underset{(White)}{{CuSO}_{4}} + 5 H_{2} O ⟶ \underset{(Blue)}{{CuSO}_{4} \cdot 5 H_{2} O}$

Write the chemical formula of hydrated copper sulphate and anhydrous copper sulphate. Giving an activity illustrate how these two are interconvertible.

Important Questions on Acids, Bases And Salts

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