Question

When blue salt of copper sulphate is heated it becomes colourless ?

Answer 1

On heating the blue salt of copper sulphate it is seen that it becomes colourless.

This is so because the salt strongly looses all the water of crystallization, which leads to the formation of anhydrous copper sulphate which is white in colour.

The salt containing water crystallization is called hydrated salts.

Answer 2

HEY!!

✴Copper sulphate  contains 5 molecules of water of crytsallisation.

✴These 5 molecules of water of crytsallisation are responsible for the blue colour of the salt.

✴When copper sulphate is heated, the water molecules are lost on heating which males the copper sulphare colourless.

✴✴CuSO4 5H2O --- CuSO4 + 5H2O