A solution containing a mixture of metal cations was treated with dilute HCl and a precipitate formed. The solution was filtered, and H2S was bubbled through the acidic solution. A precipitate again formed and was filtered off. Then, the pH was raised to about 8 and H2S was again bubbled through the solution. This time, no precipitate formed. Finally, the solution was treated with a sodium carbonate solution, which resulted in the formation of a precipitate. Classify the metal ions based on whether they were definitely present, definitely absent, or whether it was possible they were present in the original mixture. 1. Cu2+
2. Sb3+
3. Pb2+
4. Ca2+
5. Hg2^2+
6. Fe2+
7. Al3+
8. Sn2+
9. Li2+
10. Mg2+
11. Hg2+
12. Ag+
a. definitely present
b. definitely absent
c. possibly present