Chemistry: Saturated Solution and Equilibrium

What is the state of the solution in the flask after a student adds solid KCl and thoroughly shakes it?

A) saturated and is at equilibrium with the solid KCl

B) saturated and is not at equilibrium with the solid KCl

C) unsaturated and is at equilibrium with the solid KCl

D) unsaturated and is not at equilibrium with the solid KCl

Answer:

Option (A) saturated and is at equilibrium with the solid KCl

When a student adds solid KCl to water in a flask and shakes it until no more solid KCl dissolves, the solution in the flask is considered saturated. This means that the solution cannot dissolve any more KCl as some solid KCl remains visible in the flask.

Moreover, the solution is also at equilibrium with the solid KCl. Equilibrium is reached in a chemical reaction when there is no observable change in the system over time. In this case, since some KCl remains visible in the flask even after thorough shaking, it indicates that the solution is in equilibrium with the solid KCl, meaning no further dissolution of KCl occurs.