What is meant by "water of crystallisation" in a substance? Explain with an example.
he water molecules that form part of the structure of a crystal of a salt are called water of crystallisation. For example, washing soda crystals (or sodium carbonate crystals) contain 10 molecules of water of crystallisation in one formula unit. It is represented as, Na2CO3.10H2O. It is also called sodium carbonate decahydrate the last part of name coming from ten molecules of water present in the crystal structure.