Ba+2: 6: carbonates, hydroxides, oxides, phosphates and sulfides are all insoluble, these rules have to be followed in order, eg: rule 1 tales precedence over rule 2 etc. Precipitation reactions: reactions where an insoluble solid product is formed. If the attractive forces between the solvent molecules and the particles of the solute is stronger than the forces holding the solid together, then the solute will dissolve in the solvent. Solubility of ionic compounds: not all ionic compounds will dissolve completely in water, soluble: a compound is given this term is it dissolves in water. In a polyatomic ion the sum of the oxidation states of all the atoms that make it up must equal the charge of the ion: eg: in the polyatomic ion no3. = reduction (o2 has gained electrons: 2 mg + o2 2mgo. Chma10 lecture 3: reaction stoichiometry, yields, and solution concentrations. Disproportion reactions: reactions where a reactant undergoes both oxidation and reduction.