Question

A solution containing a mixture of metal cations was treated as follows. 1. Dilute HCl was added and a precipitate formed. The precipitate was filtered off. 2. H,S was bubbled through the acidic solution. Again, a precipitate formed and was filtered off. 3. The pH was raised to about 9 and H, S was again bubbled through the solution. No precipitate formed. 4. Finally, sodium carbonate was added and no precipitate formed. What can be said about the presence of each of these groups of cations in the original solution? Description Present in the original solution? form insoluble chlorides Cation Group Ag+, Pb2+, Hg Bi+, Cd2+, Cu²+, Hg²+, Pb2+, Sb3+, Sn?". Snº+ A18+, Co2+, Cr3+, Fe²+, Fe3+, Ni?, Mn, Zn²+ Ba2+, Ca2+, Mg2+, Sr?+ form acid-insoluble sulfides form base-insoluble sulfides or hydroxides form insoluble carbonates Li+, Na+, K+, NH} completely soluble Answer Bank All of these ions were present At least one of these ions was present None of these ions were present

Answer 1

O After addition Precipitate was At least group that are present of dilute to a formed, one of the cation form insoluble chlorily - ② Now, H₂S was bubbled and on through the acidic solution and again Precipitate was formed this implies that the ions that form acid in soluble Sulphides must at least One of them must be present. ® The pH was raised to about 9 and again no precipitate was formed after bubbling through solution * The cations that form base.ca insoluble sulfides or hydronide must not be present. as there is no presipdate. % sodium carbonate was added . and no precipalate was formed * A cation that form insoluble carbonate must not be present,

cation Group Present in Solution the original He 2+ | Agt, Pg2t , Hg2+ . At these least one of ions was present least one of these / was present of Bizt, Cd2+ cult, Hg2+ At [P624 , 563t, sp2t, sight ions Ba²+, Ca2+, Mght, sq?+ None were Bat Ca2+, ng2t , sq 24 Rheart mat cat none I were Lit, wat, kt, what can't these present ions of these present cons. comment *

* We group can't from comment the on above these ceations treatement.