CHEM 1312H 1st Edition Lecture 3217.4 SOLUBILITY EQUILIBRIAThe Solubility Product Constant, Ksp- a saturated solution is one in which the solution is in contact with un-dissolved soluteo the extent to which the dissolution reaction occurs is expressed by the magnitude of the equilibrium constant, which expresses how soluble a solid is in watero Ksp writing rules are the same for Kc rules (products over reactants, no solids, etc.)o ifKsp is small, only a small amount of the solid dissolves in water at a certain temperatureSolubility and Ksp- solubility: the quantity that dissolves to form a saturated solution (typically g/L)o solubility of a substance changes considerably in response to a number of factors; pH of solution, concentrations of other ions in a solution (especially common ions)- Ksp: the equilibrium constant for the equilibrium between an ionic solid and its saturated solution (no units)o Kspis one set value for a given solute at any one temperature17.5 FACTORS THAT AFFECT SOLUBILITY1) Presence of a Common IonIf you have CaF2 (s)  Ca2+ (aq) + 2F- (aq)the presence of either Ca2+ or F- will shift the equilib. concentrations to the left and reduce the overall solubility of CaF22) pHThe solubility of any ionic compound that contains a basic anion (the anion of a weak acid) increases as the solution becomes more acidic (as more H+ is present). For instance, Mg(OH)2(s)) becomes a lot more soluble as the acidity of the solution increases.3) Formation of Complex IonsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.For example; AgCl’s solubility is increased in the presence of NH3 because NH3 is a Lewis base, which attracts the Ag+ ions that form after AgCl dissolves. The presence of NH3 drives the dissolution of AgCl to the right.In order for a Lewis base to increase the solubility of a metal salt, the base must be able to interact more strongly with the metal ion than water can. Something like Ag(NH3)2+ is a complex ion, which are very soluble in water. The equilibrium constant for the formation of a complex ion is called Kf, and its magnitude tells us the stability of the complex ion in aqueous solution.Other common Lewis bases that increase metal salt solubility are CN- and OH-.- Amphoterismo amphoteric oxides and hydroxides are soluble in strong acids and bases because they’recapable of behaving as either an acid or base themselveso examples: Al3+, Cr3+, Zn2+, Sn2+o metal hydroxides such as Ca(OH)2 and Fe(OH)3 can dissolve in acidic solution but can’t react with excess base and therefore aren’t amphoteric17.6 PRECIPITATION AND SEPARATION OF IONS- How can we predict whether a precipitate will form under various conditions?o Q is the reaction quotient that can determine the direction in which a rxn will proceed toreach equilibrium if Q = Ksp, the system is at equilibrium; the solution is saturated if Q <Ksp, the reaction will proceed to the right, towards the soluble ions; no preciipate will form if Q >Ksp, the reaction will shift left and a precipitate will form- Selective Precipitation of Ions: when ions are separated from each other based on the solubilites of their saltso for ex, if a solution has both Ag+ and Cu2+, adding HCl to the solution will cause AgCl to precipitate will Cu2+ will remain in the solution because CuCl2 is still soluble17.7 QUALITATIVE ANALYSIS FOR METALLIC ELEMENTS- Qualitative analysis: determines the presence of absence of a particular metal ion relative to some threshold- Quantitative analysis: determines how much of a given substance is present- both proceed in three stages:o the ions are separated into broad groups based on solubility propertieso the ions in each group are separated by selectively dissolving members in the groupo the ions are identified by the conductance of specific