The blue colour of crystals of a substance changed on heating in a closed test tube but the colour was regained after sometime on cooling. Name the substance and write it's phenomenon. Explain the phenomenon involved
Answers
Explanation:
The substance is hydrated copper sulphate (CuSO4 . 5H2O) which looses its water of crystallization on heating in a closed vessel and so its color changes from blue to white but when the vessel is allowed to cool the water vapor again condensed to for the copper sulphate pentahydrate and the color is regained.
Explanation:
Crystals of a substance which changed their colour on heating in a closed test tube but regained it after sometime when they were allowed to cool down are copper sulphate or more specifically hydrated copper sulphate.
Its formula - CuSO4.5H2O
The phenomena involved is due to the presence of molecules of water of crystallization in the molecule. Water of crystallization is the fixed number of water molecules that are present in one formula unit of a salt. When we heat the crystals of hydrated copper sulphate this water is removed and the salt turns white. But when it is allowed to cool down in open air then it regains its lost water of crystallization and hence regains its colour also.
verified