During a lab, students mixed K2CO3 and CaCl2 solutions and formed a precipitate. What is the correct net ionic equation for this reaction?

The formation of a precipitate during the mixing of K2CO3 and CaCl2 solutions indicates a double displacement reaction where ions in the solution exchange partners. In this case, calcium ions (Ca2+) from calcium chloride react with carbonate ions (CO32-) from potassium carbonate to form calcium carbonate (CaCO3), which is insoluble in water and precipitates out of the solution.

To write the net ionic equation, only the species that participate in forming the precipitate are included. The calcium ions and carbonate ions are the reactive components, resulting in the formation of the solid precipitate, CaCO3. This is why the net ionic equation is represented as the combination of these two ions leading to the formation of a solid compound.

The other options represent either full compounds that do not indicate a reaction or involve ions that do not lead to the formation of a precipitate. Therefore, recognizing the specific ions that precipitate is essential in identifying the correct net ionic equation.