What is meant by hydration in chemistry?

Hydration in chemistry specifically refers to the process of adding water to a substance. This concept is particularly significant in various chemical reactions, especially when discussing solvation, where water molecules surround and interact with solute ions or molecules. In many reactions, particularly those involving ionic compounds, the addition of water can lead to the formation of hydrated ions or molecules, which may alter their properties and behaviors in solution.

For example, when anhydrous salt (like copper(II) sulfate) is mixed with water, it undergoes hydration, transforming into blue hydrated copper(II) sulfate. This process illustrates how water plays a critical role in dissolving solids and influencing the outcome of chemical reactions. Other options, such as removing water or evaporating a liquid, do not capture the essence of hydration, which is fundamentally about the introduction of water to enhance or facilitate a chemical interaction.