write the reaction for the dehydration of CuSO4 . XH20?
CuSO4.5H2O ==> CuSO4 + 5H2O
Why is it 5 H2O?
You had X. The USUAL amount of water of crystallization in CuSO4 is 5 mols H2O so I used that number. If you rather I had used X, then
CuSO4.XH2O ==> CuSO4 + XH2O