Solubility is best defined as the ability of a substance to dissolve in a solvent.

• A. The color of a solution
• B. Ability of a substance to dissolve in a solvent
• C. The hardness of a material
• D. The smell of a substance

Answer: (B)

Solubility is about how much of a substance can dissolve in a solvent at a given temperature, forming a single, uniform solution. That idea is captured by saying it’s the ability of a substance to dissolve in a solvent.

Think of it this way: table salt readily dissolves in water, while oil does not mix with water and remains separate. The look, texture, or scent of a substance—its color, hardness, or smell—do not tell you how well it can dissolve. Those are separate properties, not measurements of solubility. Solubility focuses on the extent of dissolution and what fraction of the substance can become dissolved under specific conditions, not on how fast it happens (that’s the rate of dissolution) or how it appears.