If a sample of AgCL is shaken with excess water and concentrated solution of sodium chloride, how would the equilibrium be affected
When a sample of AgCl (silver chloride) is shaken with excess water and a concentrated solution of sodium chloride (NaCl), the equilibrium of the dissolution-precipitation reactions of AgCl can be affected. Let's break down the process and analyze how the equilibrium is influenced.
1. Initial State:
In the beginning, the AgCl solid is in contact with water, resulting in a very limited dissolution of AgCl. The equilibrium can be represented as follows:
AgCl(s) ⇌ Ag+(aq) + Cl-(aq)
2. Addition of Sodium Chloride Solution:
When a concentrated solution of sodium chloride (NaCl) is added, the system becomes dominated by the excess chloride ions (Cl-) from NaCl. These chloride ions will interact with the silver ions (Ag+) formed during the dissolution of AgCl, leading to the formation of silver chloride again. This reaction can be represented as:
Ag+(aq) + Cl-(aq) ⇌ AgCl(s)
3. Effect on Equilibrium:
The addition of excess chloride ions from the sodium chloride solution causes a shift in the equilibrium towards the production of AgCl(s). According to Le Chatelier's principle, adding more chloride ions will force the equilibrium to shift in the reverse direction to reduce the concentration of Ag+ ions.
As a result of this shift, more AgCl(s) will be formed, and the dissolution of AgCl will decrease. This can be explained by the common ion effect, where the presence of a common ion (in this case, Cl-) reduces the solubility of a sparingly soluble salt (AgCl).
Overall, the equilibrium is disrupted by the addition of excess chloride ions, favoring the precipitation of AgCl rather than its dissolution.
It is important to note that while the addition of sodium chloride affects the equilibrium, it does not completely dissolve the AgCl since AgCl is only sparingly soluble in water.