Compare the solubility of silver iodide in each of the following aqueous solutions:
0.10 M AgNO3 0.10 M Nal 0.10 MNHẠCH,COO 0.10 M NaNO3 Clear All More soluble than in pure water. Similar solubility as in pure water. Less soluble than in pure water.
The Correct Answer and Explanation is :
To determine the solubility of silver iodide (AgI) in different aqueous solutions, we need to consider the effects of the ions present in these solutions on the solubility product of silver iodide. The solubility product (Ksp) for AgI is 1.5×10−161.5 \times 10^{-16}, indicating it is very slightly soluble in water. The presence of common ions in the solution can shift this solubility due to the common ion effect. Let’s analyze each solution:
- 0.10 M AgNO3 – This solution contains the common ion Ag+^+. According to Le Chatelier’s principle, the addition of a common ion will decrease the solubility of a compound in a solution because it shifts the dissolution equilibrium towards the left (precipitate formation). Therefore, the solubility of AgI in this solution is less soluble than in pure water.
- 0.10 M NaI – This solution contains the common ion I−^-. Similar to the effect of Ag+^+ in AgNO3 solution, the presence of I−^- will also decrease the solubility of AgI by shifting the equilibrium towards the formation of solid AgI. Therefore, the solubility of AgI in this solution is also less soluble than in pure water.
- 0.10 M NH4_4CH3_3COO – Ammonium acetate (NH4_4CH3_3COO) dissociates into NH4_4^+ and CH3_3COO−^- ions in water. Neither of these ions is a common ion for AgI, nor do they form complexes with Ag+^+ or I−^- that would significantly affect their concentrations. Therefore, the solubility of AgI in this solution should be similar to that in pure water.
- 0.10 M NaNO3 – Sodium nitrate (NaNO3) dissociates into Na+^+ and NO3_3^- ions. Again, neither of these ions is a common ion for AgI, and they do not interact significantly with Ag+^+ or I−^-. Thus, the solubility of AgI in this solution should also be similar to that in pure water.
The decreased solubility in the presence of common ions (AgNO3 and NaI solutions) results from the solubility product being exceeded when additional identical ions are present, pushing the dissolution reaction to precipitate more solid. In the cases of NH4CH3COO and NaNO3, no additional common ions are present to shift the equilibrium significantly, thus maintaining the solubility close to that in pure water.
Let’s generate an image that visualizes this concept.
Here is the diagram visualizing the solubility of silver iodide (AgI) in different aqueous solutions. It illustrates the effects of different ions present in each solution on the solubility of AgI, using clear symbols to indicate whether the solubility is less or similar to that in pure water. This should help in understanding how different ions influence the dissolution process. You can click on the image for a closer look.
