Which term describes the balance between dissolved ions and undissolved solid in a saturated solution?

The term that best describes the balance between dissolved ions and undissolved solid in a saturated solution is dynamic equilibrium. In a saturated solution, the rates of dissolution of the solid and the rates of precipitation of the solid are equal, resulting in a state where the concentration of dissolved ions remains constant over time, even though the processes of dissolution and precipitation are continually occurring. This constant interplay indicates that the system is actively maintaining balance, hence the term "dynamic."

In contrast, static equilibrium refers to a situation where there is no movement or exchange, which does not apply to a saturated solution where the processes are ongoing. Chemical equilibrium pertains to the overall balance of reactants and products in a chemical reaction and isn't limited to the context of solid and dissolved states. Physical equilibrium is a broader term that can incorporate various physical processes but does not specifically capture the ion-dissolved solid interplay as well as dynamic equilibrium does.