A solution is 0.0100 M in each of the metal ions in the following table: Metal sulfide Kspa
FeS 6×102
NiS 8×10−1
PbS 3×10−7
CuS 6×10−16
a) HCl is added to the solution so that the H3O+ concentration is 0.300 M. H2S gas is bubbled through the solution to attain a H2S concentration of 0.100 M. Predict which of the sulfides precipitate under the given conditions
Which will Precipitate and which will not?
b)The solution remaining from Part A, which contains 0.0100 M Ni2+ and Fe2+ ions, is still saturated with H2S gas, producing a concentration of 0.100 M. A buffer is added to this solution to produce a pH of 2.01 . Which of the following describes correctly the effect of the addition of the buffer?
a) Only NiS precipitates.
b) Only FeS precipitates.
c) Both NiS and FeS precipitate.
d) Neither NiS nor FeS precipitate.