What happen when blue colour of CuSO4.5H2O is heated

1.	What happen when blue colour of CuSO4.5H2O is heated
Answer» The blue colour is due to the water of crystallization (CuSO4.5H2O). When this is removed by heating, basic copper sulphate is left (CuSO4.H2O) and this can be further broken to simple CuSO4. It is essential you realize the water is not there as free liquid, but as a molecule in its own right and it is bound to the copper atom.In the case of all transition metals, the water of hydration is linked to the d (or higher) orbitals and these distort slightly, thereby causing a band energy shift that is characterized by the colour. In the case of copper this shift is in the 600-900 nm region and this is where the blue-green colours occur.

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