Question

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 formation of a precipitate. which metal ions were definitely present, which were definitely absent, and which may or may not have been present in the original mixture?

Answer 1

If you really keep an eye on the flow chart, the only ions you can consider as being "Definitely not present" are: Cr3+, Fe3+, and Zn2+. The rest of the ions should be considered under "Possibly present", as we cannot conclude if any of the ions are "Definitely present".