The solubility of silver chloride in water decreases when sodium chloride is added. This is an example of
- A. the common ion effect
- B. the buffer action
- C. hydrolysis
- D. the catalytic effect
Explanation
Sodium chloride supplies extra chloride ions, and since the ionic product must not exceed Ksp the equilibrium shifts towards the undissolved solid, so less silver chloride can dissolve. This is Le Chatelier's principle applied to a solubility equilibrium and is used deliberately to wash a precipitate without dissolving it. Adding an ion not present in the salt would not have this effect.