A solution contains one or more of the following ions: Hg₂²⁺, Ba²⁺, and Fe²⁺. When you add potassium chloride to the solution, a precipitate forms. The precipitate is filtered off, and you add potassium sulfate to the remaining solution, producing no precipitate. When you add potassium carbonate to the remaining solution, a precipitate forms. Write net ionic equations for the formation of each of the precipitates observed.

Key Concepts

Solubility Rules

Solubility rules are guidelines that help predict whether a compound will dissolve in water. For example, most chlorides are soluble, except for those of silver, lead, and mercury. In contrast, sulfates are generally soluble, but barium sulfate is an exception. Understanding these rules is crucial for determining which ions will precipitate when mixed.

Precipitation Reactions

Precipitation reactions occur when two soluble salts react in solution to form an insoluble compound, known as a precipitate. This process can be represented by net ionic equations, which focus on the ions that participate in the formation of the precipitate. Identifying the ions involved and their solubility is essential for writing accurate equations.

Net Ionic Equations

Net ionic equations represent the actual chemical species that participate in a reaction, excluding spectator ions that do not change during the reaction. To write a net ionic equation, one must first identify the reactants, determine the products, and then eliminate the ions that remain unchanged. This simplification helps clarify the essential chemical changes occurring in the reaction.