A solution contains one or more of the following ions: Pb 2+, Ca 2+, and Zn 2+. When sodium chloride is added to the solution, a precipitate forms. The precipitate is filtered off and sodium sulfate is added to the solution, but no percipitate forms. When sodium carbonate is added to the soultion, however, a precipitate forms. Which ions were present in the original solution? What are the net ionic equations for each reaction that occured?