In a saturated solution at a given temperature, the undissolved solutes are in equilibrium with

In a saturated solution, the undissolved solute particles and the dissolved solute particles are in a dynamic equilibrium. This means that at a given temperature, the rate at which solute particles dissolve into the solvent is equal to the rate at which solute particles come out of solution and reform the solid. Therefore, the undissolved solute particles are in equilibrium with the saturated solution, which is the solution that contains the maximum amount of solute that can dissolve at a given temperature. This equilibrium occurs because the solute particles have reached their maximum solubility limit and are unable to dissolve any further. In summary, the undissolved solute particles are in equilibrium with the saturated solution, not with the solvent or the insoluble solute particles.