19) A solution contains equal concentrations of Hg2+(aq), Pb2+(aq) and Fe2+(aq)
ID: 976422 • Letter: 1
Question
19) A solution contains equal concentrations of Hg2+(aq), Pb2+(aq) and Fe2+(aq) ions. When a solution of S2-(aq) is slowly added to this solution, the precipitate which forms first is: (Use Ksp values for HgS, PbS and FeS given)
A) HgS 1.6*10^-54
B) PbS 7.0*10^-29
C) FeS 3.7*10^-19
20) A solution contains Hg2+(aq), Pb2+(aq) and Fe2+(aq) ions. When a solution of S2-(aq) is slowly added to this solution, the precipitate which forms last is: A) HgS B) PbS C) FeS 21) The [SO42-]
The [SO4 2-] in a saturated solution of PbSO4 is (Ksp = 1.1 x 10-8)
A) 1.5X10-16 M B) 1.8X10-4 M C) 1.1X10-8 M D) 1x10-4 M
Explanation / Answer
19.
the first to precipitate is that with the lowest Ksp value
in this case, HgS precipitates first
20.
we can compare directly so
Hg will precipitate first
21.
KSp = [Pb+2][SO4-2]
1.1*10^-8 = S*S
S = sqrt(1.1*10^-8) = 1.04880*10^-4
choose D
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.