We're being asked to determine in which of following aqueous solutions would you expect AgCl to have the lowest solubility.
The common ion effect states that the solubility of a salt is lower in the presence of a common ion.
Since the compounds are ionic compounds, they form ions when dissociating in water. We're going to calculate the solubility of AgCl in each of the solution given:
A. 0.020 KCl
KCl(aq) ⇌ K+(aq) + Cl‒(aq)
AgCl(s) ⇌ Ag+(aq) + Cl–(aq); Ksp = 1.77×10–10
Notice that there is a common ion present, Cl–.
We can construct an ICE table for the dissociation of AgCl. Remember that solids are ignored in the ICE table.
In which of the following aqueous solutions would you expect AgCl to have the lowest solubility?
A) 0.020 KCl
B) pure water
C) 0.015 NaCl
D) 0.020 AgNO3
E) 0.020 M BaCl2