Question

What do you observe when penta hydrated copper sulphate and heated give reasons?

Answer 1

Copper sulphate is a hydrated salt which contains 5 molecules of water of crytsallisation, and so is denoted by the chemical formula CuSO4.5H2O. These 5 molecules of water of crytsallisation are responsible for the blue colour of the salt. However, when copper sulphate is heated for some time, the blue colour disappears and it becomes white-gray in colour. This is because the water molecules are lost on heating and copper sulphate pentahydrate is converted to anhydrous copper sulphate. 

Answer 2

blue colour change into white