Copper sulphate crystals which seem to be dry contain water of crystallisation. When we heat the crystals, this water is removed and the salt turns white. If you moisten the crystals again with water, you will fnd that blue colour of the crystals reappears. Later of crystallisation is the fixed number of water molecules present in one formula unit of a salt. Five water molecules are present in one formula unit of copper sulphate. Chemical formula for hydrated copper sulphate is \(CuSO_4.5H_2O.\) the molecule of \(Na_2CO_3.10H_2O\) is wet.
1. Does copper sulphate crystals contain water of crystallization?
(i) YES
(ii) NO
2. When we heat the crystals of copper sulphate the salt colour turns_____.
(i) Black
(ii) White
3. What is the chemical formula of hydrated copper sulphate?
(i) \(CuSO_4.5H_2O\)
(ii) \(CuSO_3.3H_2O\)
4. How many water molecules are there in one unit of copper sulphate?
(i) Four
(ii) Five
5. State True or False. Water of crystallisation is the random number of water molecules present in one formula unit of a salt
(i) TRUE
(ii) FALSE
