Chemistry 11 : Cations and Anions Solubility

Ionic substances tend to dissolve in polar (or ionic) solvents Because of the high melting points of ionic compounds, ionic solutions are uncommon

Factors that affect the solubility of ionic compounds Ion charge The higher the ion charges, the lower the solubility of the compounds, when    ionic compounds dissolve

⇒  When ionic compounds dissolve, the ionic bonds must be broken ⇒  The higher the ionic charges, the stronger the ionic bond

Ion size Larger ions have a higher solubility than compounds than smaller ions Ionic bonds involving larger ions are weaker because the ions are further apart and the charge is spread over a large volume

For aqueous solutions of ionic compounds, the following chart can be used to predict the solubility of ionic compounds (p.334)



The lower the guideline number, the more important the guideline

Na2CO3 – Soluble - > Guideline 1 CaCl2 - Soluble - > Guideline 3 MgO – Insoluble ->Guideline 2 Ag2SO4 -> Insoluble -> Guideline 2 FePO4 -> Insoluble - > Guideline 2 FeCl2 -> Soluble -> Guideline 3 Ba(OH)2 -> Soluble -> Guideline 2

Chapter 9-A