Explain the following statement. A saturated solution contains a mixture of silver chloride, AgCl and silver carbonate, Ag2CO3. An addition of hydrocloric acid will decrease the solubility of AgCl
Adding a common ion to an insoluble salt decreases the solubility of the salt.
Cl from the HCl is the common ion (to Cl in AgCl).
To understand the statement, let's break it down step by step.
A saturated solution is a solution that has reached its maximum solubility limit at a particular temperature and pressure. In this case, it contains a mixture of two substances: silver chloride (AgCl) and silver carbonate (Ag2CO3).
Now, let's focus on the effect of hydrochloric acid (HCl) on the solubility of AgCl in the saturated solution.
When HCl is added to the solution, it will provide chloride ions (Cl-) into the system. These chloride ions can react with the silver ions (Ag+) present in the solution.
The reaction between chloride ions and silver ions can be represented by the following equation:
AgCl(s) + Cl-(aq) ↔ AgCl2-(aq)
This reaction results in the formation of a soluble complex ion called the tetrachloroargentate ion (AgCl2-). This soluble complex is formed due to the interaction between Ag+ from AgCl and Cl- from HCl.
As a result, by forming the tetrachloroargentate complex, the concentration of free Ag+ ions in the solution decreases. This reduction in the concentration of Ag+ ions decreases the solubility of AgCl in the saturated solution.
In simpler terms, when hydrochloric acid is added to the mixture of AgCl and Ag2CO3, it leads to the formation of a soluble complex, which removes some of the silver ions from the solution. This effectively reduces the availability of silver ions to keep the AgCl dissolved, causing a decrease in the solubility of AgCl.
Therefore, the statement is saying that the addition of hydrochloric acid will reduce the solubility of AgCl in the saturated solution.