What term describes a solution that contains less than the maximum amount of dissolved solute?

• A. Saturated
• B. Unsaturated
• C. Supersaturated
• D. Concentrated

Answer: (B)

Solubility and saturation describe how much solute a solvent can hold at a given temperature. When a solution has not yet reached the limit of how much solute can dissolve, it is unsaturated. In an unsaturated solution, you can still dissolve more solute at that temperature because the solvent has not yet reached its maximum capacity to hold dissolved particles.

For example, if water can dissolve up to a certain amount of sugar at a given temperature and you’ve dissolved less than that amount, you could add more sugar and it would still dissolve. Once you reach that limit, the solution becomes saturated and additional solute won't dissolve. If you somehow have more than the maximum dissolved (often by changing conditions like cooling a saturated solution), you have a supersaturated solution, which is unstable and can crystallize. A concentrated solution simply has a high amount of solute relative to solvent, but this does not by itself indicate whether it’s unsaturated or saturated.