Which solution contains more solute than can be dissolved?

A supersaturated solution is one that contains more solute than can be dissolved at a given temperature and pressure. This occurs when a solution is prepared at an elevated temperature, allowing more solute to dissolve than would normally be possible at a cooler temperature. As the solution cools, the solute remains dissolved even at concentrations exceeding its normal solubility limit, leading to a state of supersaturation. This state is often unstable, and any disturbance can lead to the excess solute crystallizing out of the solution.

In contrast, a saturated solution contains the exact amount of solute that can be dissolved at a given temperature, creating a dynamic equilibrium between the dissolved solute and the undissolved solute. An unsaturated solution, on the other hand, has the capacity to dissolve more solute, while a concentrated solution refers to a solution with a relatively high amount of solute dissolved in it, but it does not imply that it exceeds the solubility limit. Therefore, the definition of supersaturation clearly identifies it as the only option containing more solute than can typically be dissolved, justifying why it is the correct answer.