17.4.2 CIA Demonstration: Silver Chloride and Ammonia

Question 1

CIA Demonstration: Silver Chloride and Ammonia

Answer 1

• The solubility product constant (K sp ) is the equilibrium constant which governs the equilibria of sparingly soluble salts.
• Le Châtelier’s principle states that when a stress is applied to a system in equilibrium, the system will shift in such a way as to relieve the stress.

Question 2

note

Answer 2

• The experiment begins with the reaction of potassium chloride (KCl) and silver nitrate (AgNO 3 ) to make silver chloride (AgCl), a milky white product.
• Ammonia is added to this solution. The ammonia complexes with the silver and forms a silver ammonia complex ion. Once enough ammonia is added, the solution clears.
• According to Le Châtelier’s principle, as the silver is
  removed, the silver chloride continues to dissolve to form more silver and chloride ions until all of the silver is complexed and the solution is essentially clear.
• Hydrochloric acid is added to the resulting solution.
• As the hydrochloric acid is added it will react with the
  ammonia to form ammonium chloride, which is soluble. This will free up the silver ions, driving the reaction back to the silver chloride. This is also explained by Le Châtelier’s principle.