Which of the following compounds crystallizes without water of crystallization?
Answer Details
The compound that crystallizes without water of crystallization is sodium chloride (NaCl). When a compound crystallizes, it can trap water molecules within the crystal lattice, forming a hydrated compound. These water molecules are called water of crystallization. However, NaCl is an ionic compound that does not have water of crystallization. This is because ionic compounds do not have a defined molecular structure that can incorporate water molecules. NaCl is formed by the ionic bond between sodium and chloride ions. Therefore, when it crystallizes, it does not include any water molecules in the crystal structure. On the other hand, the other compounds listed have a defined molecular structure that can incorporate water molecules in the crystal lattice, forming hydrated compounds. For example, magnesium sulfate (MgSO4) can crystallize with 7 water molecules in the lattice, forming MgSO4·7H2O. Sodium carbonate (Na2CO3) can crystallize with 10 water molecules, forming Na2CO3·10H2O. Iron(II) sulfate (FeSO4) can crystallize with 7 water molecules, forming FeSO4·7H2O.