How is the ability for substances to mix characterized?

The ability for substances to mix is characterized by the concept of miscibility. Miscibility refers specifically to the ability of two or more substances to completely dissolve in one another in any proportion, typically concerning liquids. When two liquids are miscible, they can form a homogeneous mixture without any separation, such as water and ethanol.

This property is important in various applications, including chemistry, pharmaceuticals, and food science, where certain components need to blend seamlessly to create effective solutions or mixtures. Understanding miscibility helps predict how different substances will behave when combined, influencing everything from material properties to reactions in solution.

On the other hand, viscosity measures a fluid's resistance to flow, density relates to mass per unit volume, and solubility focuses on how substances dissolve in a solvent, particularly solids in liquids, making those concepts less applicable to the specific characteristic of mixing expected in this context.