Which ions remain in solution, unreacted, after each of the following pairs of solutions is mixed? (a) potassium carbonate and magnesium sulfate

Verified step by step guidance

1. Identify the ions present in each solution: Potassium carbonate (K2CO3) dissociates into 2 K^+ ions and 1 CO3^2- ion. Magnesium sulfate (MgSO4) dissociates into 1 Mg^2+ ion and 1 SO4^2- ion.
2. Determine the possible products of the reaction: When these solutions are mixed, the possible products are magnesium carbonate (MgCO3) and potassium sulfate (K2SO4).
3. Consider the solubility rules: Magnesium carbonate (MgCO3) is generally insoluble in water, while potassium sulfate (K2SO4) is soluble.
4. Predict the precipitate: Since MgCO3 is insoluble, it will precipitate out of the solution, leaving the other ions in solution.
5. Identify the ions remaining in solution: The ions that remain in solution are the ones that do not form the precipitate, which are K^+ and SO4^2- ions.

Key Concepts

Solubility Rules

Solubility rules are guidelines that help predict whether a compound will dissolve in water. For example, most alkali metal salts, like potassium carbonate, are soluble, while some sulfates, such as those of barium and lead, are insoluble. Understanding these rules is crucial for determining which ions remain in solution after mixing different compounds.

Precipitation Reactions

A precipitation reaction occurs when two soluble salts are mixed, resulting in the formation of an insoluble compound that precipitates out of solution. In the case of potassium carbonate and magnesium sulfate, the potential formation of magnesium carbonate, which is insoluble, must be considered to identify which ions remain in solution.

Ionic Equations

Ionic equations represent the species present in a solution and help visualize the interactions between ions. By writing the complete ionic equation for the reaction between potassium carbonate and magnesium sulfate, one can identify the spectator ions—those that do not participate in the reaction and remain unreacted in the solution.