Step 1: Understanding the Concept:
The common ion effect is an application of Le Chatelier’s principle to ionic equilibria.
Step 3: Detailed Explanation:
When a strong electrolyte and a weak electrolyte containing a common ion are dissolved in the same solution, the strong electrolyte dissociates completely, increasing the concentration of the common ion.
According to Le Chatelier’s principle, the equilibrium of the weak electrolyte shifts in the direction that consumes the common ion (the reverse direction).
As a result, the degree of dissociation of the weak electrolyte decreases.
Example: Adding \(CH_3COONa\) (strong) to \(CH_3COOH\) (weak) suppresses the ionization of acetic acid.
Step 4: Final Answer:
The common ion effect is the reduction in solubility or ionization of an electrolyte when another compound containing the same ion is added.