A solution containing a mixture of metal cations was treatedwith dilute HCl and no precipitate formed. Next H2S was bubbledthrough the acidic solution. A precipitate formed and was filteredoff. Then the pH was raised to about 8 and H2S was again bubbledthrough the solution. A precipitate again formed and was filteredoff. Finally the solution was treated with a sodium carbonatesolution which resulted in no precipitation. Which metal ions weredefinitely present which were definitely absent and which may ormay not have been present in the original mixture? Ag+ Hg2^2+Pb2+ Sn2+ Mg2+ Al3+ Li+ Ca2+ Cu2+ Hg2+ Ni2+ Sb3+