The solubility of silver chloride AgCl in water is affected by the common ion effect when the concentration of sodium chloride NaCl is increased. The common ion effect occurs when two substances that share a common ion are in equilibrium in a solution, and the addition of one of the substances affects the solubility of the other.In the case of AgCl and NaCl, the common ion is the chloride ion Cl- . The solubility equilibrium of AgCl in water can be represented by the following equation:AgCl s Ag+ aq + Cl- aq The solubility product constant Ksp for this reaction is given by:Ksp = [Ag+][Cl-]When NaCl is added to the solution, it dissociates completely into its ions:NaCl s Na+ aq + Cl- aq As the concentration of NaCl increases, the concentration of Cl- ions in the solution also increases. According to Le Chatelier's principle, when a change is made to a system in equilibrium, the system will adjust to counteract the change and re-establish equilibrium. In this case, the increase in Cl- concentration will shift the equilibrium of the AgCl solubility reaction to the left, causing more AgCl to precipitate out of the solution and reducing its solubility.In summary, increasing the concentration of sodium chloride solution will decrease the solubility of silver chloride in water due to the common ion effect and Le Chatelier's principle. The increased concentration of chloride ions from the sodium chloride will shift the solubility equilibrium of silver chloride to favor the formation of solid AgCl, resulting in a decrease in its solubility.