Determine and apply Ksp values to calculate solubility, concentrations, and rela

Question

Determine and apply Ksp values to calculate solubility, concentrations, and related quantities for insoluble substances in aqueous neutral, basic and acidic solutions. . A solution is 0.20 M in Cu(II), Pb(II), and Ni(II). Upon the addition of aqueous sodium sulfide to the solution, which sulfide would precipitate out of solution first? ________________ [Ksp values: CuS is 6x10 -36, PbS is 3x10 -27, and NiS is 3x10 -19 ] If the solubility of strontium fluoride, SrF2, is 0.073 g/L, what is the value for Ksp?

Explanation / Answer

We have Ksp values of CuS - 6x10 -36, PbS - 3x10 -27, and NiS - 3x10 -19

The solution has same amount (0.20M) of the ions Cu2+ , Pb2+ and Ni2+

For a substance to precipitate out first, ionic product must exceed solubility product.

Ionic product of all the compounds is same as we have same amount of divalent cation and the sulfide ion.

So now we look at the compound with least Ksp (solubility product). The compound with least Ksp precipitates out first. So, CuS (Ksp :6x10 -36) precipitates out first.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------

If the solubility of strontium fluoride, SrF2, is 0.073 g/L, what is the value for Ksp?

Given that solubility s = [0.073 g/L * 1 mol SrF2/125.62 g SrF2 ]

= 5.81*10-4 M

Ksp = [Sr2+][F-]2

= s(2s)2

= 4s3

= 4(5.81*10-4)3

= 7.85*10-10

  

SrF2 (aq) <====> Sr2+ (aq) 2 F- (aq) Initial - 0 0 Change - + s +2 s Equilibrium - s 2s

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.