A solution containing a mixture of metal cations was treated with dilute HClHCl and no precipitate formed. Next, H2SH2S was bubbled through the acidic solution. A precipitate formed and was filtered off. Then, the pH was raised to about 88 and H2SH2S was again bubbled through the solution. A precipitate again formed and was filtered off. Finally, the solution was treated with a sodium carbonate solution, which resulted in no precipitation. Classify the metal ions based on whether they were definitely present, definitely absent, or whether it is possible they were present in the original mixture.