Consider the solution containing 0.181 m lead ions and 0.174
mmercury (ii) ions. the ksp for lead sulfide
is3.4*10-28 and that for mercury (ii) sulfide
is4.0*10-53. calculate the concentration in (m)
ofsulfide ions required to reduce the concentration of mercury
(ii)ions to 1.0*10-6 m?

[ S2- ] = 4.0 E-47 M

Explanation:

∴ Ksp PbS = 3.4 E-28 = [Pb2+]*[S2-]

∴ [Pb2+] = 0.181 M

∴ Ksp HgS = 4.0 E-53 = [Hg2+]*[S2-]

∴ [Hg2+] = 0.174 M

∴ Ksp PbS > Ksp HgS ⇒ precipitate first Hg2+:

∴ [ Hg2+ ] = 1.0 E-6 M

⇒ [S2-] = 4.0 E-53 / 1.0 E-6 = 4.0 E-47 M

explanation:

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