Which term describes a substance that contains no water of crystallization?

• A. Solubility
• B. Hydration
• C. Anhydrous
• D. Miscible

Answer: (C)

Water of crystallization are water molecules that are part of a crystalline compound’s structure. A substance with no water of crystallization is described as anhydrous, meaning it exists without any water bound in its lattice. This distinguishes it from hydrates, which Have a definite amount of water integrated into the crystal, such as a salt with water molecules attached (for example, a salt may be written as CuSO4·5H2O). The idea is often tested by considering how heating can remove those water molecules, leaving the anhydrous salt behind.

The other terms don’t describe the water content: solubility is about how well a substance dissolves, hydration refers to the process of forming a hydrated substance or the water that surrounds ions in solution, and miscible refers to liquids that mix together in all proportions.