Procedure:
1. Take a Small Amount: Obtain a sample of anhydrous copper sulphate. Only a small amount, such as a pea-sized portion, is needed for the test.
2. Visual Inspection: Initially, observe the colour of the anhydrous copper sulphate. Anhydrous copper sulphate typically has a white or light blue colour.
3. Add a Drop of Water: Take a glass slide or watch glass and place the small sample of anhydrous copper sulphate on it. Carefully add a single drop of water to the sample.
4. Observe Colour Change: Wait for a few seconds to observe any changes in the colour of the anhydrous copper sulphate.
Expected Results:
- Positive Test: If anhydrous copper sulphate is indeed present, upon the addition of water, the white or light blue colour of the sample will change to a deep blue colour. This change in colour indicates the absorption of water molecules by the anhydrous copper sulphate, forming hydrated copper sulphate (CuSO4.5H2O). The deep blue colour is characteristic of hydrated copper sulphate.
- Negative Test: If the anhydrous copper sulphate does not contain any significant amount of water, the colour will remain white or light blue, even after adding a drop of water.
By performing this simple qualitative analysis, you can determine the presence of water in anhydrous copper sulphate based on the observed colour change.
