Step-by-step explanation:
Whenever an ion in a solution is common for any two different salts, a common ion effect is formed that serves as the sources. Further addition of the common ion that is the product of a dissolution of the first. Adding the product ion decreases the solubility for the 1st salt.
Equilibrium made between the reactants as well as the products are described by the equilibrium constant. This expression for the insoluble salt is written using the rules that were used for other equilibriums. Equilibrium constant is known as the solubility product, Ksp.
The interactions between the ions are the results of the activity effects. The ion's activity is influenced by the surrounding. In case of water molecule, the activity of the ion has different values from the one in the middle of the counterion cloud. The Ksp values are used to decide for the order of the precipitation of any two or more of insoluble salts.