Which of the following describes what happens to the solubility of a slightly soluble ionic compound when a common ion is added to the solution? a) The solubility of the ionic compound is reduced.
b) The ionic compound dissolves more rapidly.
c) The solubility of the ionic compound is increased.
d) There is no effect on the solubility of the ionic compound.
e) More of the ionic compound dissolves.

a) The solubility of the ionic compound is reduced.

Explanation:

Let AB be the ionic compound . It will ionise as follows in solution .

         AB    ⇄    A⁺  +  B⁻

In solution AB , A⁺ and B⁻ maintain a state of equilibrium . Now if we add A⁺ ion as common ion to the solution , the equilibrium will be shifted to the left ie less of AB will ionise to maintain equilibrium . Hence the solubility of AB will be reduced .