Mole to mole conversions​

Option (A) is the correct answer.

Explanation:

When small amount of solute is added to a solvent and if it readily dissolves then this type of solution is known as an unsaturated solution.

For example, in the given situation when calcium chloride is first dissolved in water then it completely dissolves and this makes the solution unsaturated.

And, a saturated solution is defined as a solution which contains maximum amount of solute.

In the given situation, addition of further KCl won't dissolve the salt which means that the solution has become saturated. And, equilibirum is defined as a state in which the rate of forward reaction is equal to the rate of backward reaction.

Thus, we can conclude that the solution in the flask is saturated and is at equilibrium with the solid KCI.