In solutions, which property determines whether a substance dissolves in water?

• A. Viscosity
• B. Density
• C. Boiling point
• D. Solubility

Answer: (D)

Solubility tells you how much of a substance can dissolve in water. If something has high solubility, it will dissolve readily to form a solution; if it has low solubility, only a small amount will dissolve. That directly determines whether the substance can dissolve at all in water. Viscosity is about how thick a liquid is, density describes mass per volume, and boiling point is the temperature at which a liquid becomes gas, so none of those describe how much of a substance will dissolve. For example, table salt and sugar dissolve well in water because of their solubility, while oil does not dissolve well because it’s nonpolar. So solubility is the property that determines dissolution in water.