Before we talk about KSP, let's talk about the solubility of ionic compounds. Now, all ionic compounds have the ability to dissociate into their ion form when added into water. For example, let's take ionic compound sodium chloride. When we add sodium chloride chloride into water, it dissociates into two ions, sodium and chloride. Now, this reaction is called the forward reaction or dissolution. The reverse reaction is just as likely to occur, and that's called precipitation, the sufformation of ionic compound from its ion form.