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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Win,odd Dhamnekar on April 11, 2021, 01:11:28 PM

Title: [itex]K_{sp} of PbCl_2[/itex]
Post by: Win,odd Dhamnekar on April 11, 2021, 01:11:28 PM
Is author's answer correct ?

My answer:

 [itex]K_{sp}  of PbCl_2=1.7e-5[/itex], So the 13.0 M of NaCl is needed, which is impossible to obtain.

Title: Re: [itex]K_{sp} of PbCl_2[/itex]
Post by: Orcio_87 on April 11, 2021, 02:44:03 PM
Difference comes from given data - 1,7 x 10-5 and 1,0 x 10-4 for K = [Pb][Cl]2, and also that 20 ppb ≠ 1 x 10-7 M.

I get that concentration of Cl- should be bigger than 9,22  M for concentration of Pb+ lower than 2 x 10-8 M.
Title: Re: [itex]K_{sp} of PbCl_2[/itex]
Post by: Borek on April 11, 2021, 05:33:34 PM
Quote from: Orcio_Dojek on April 11, 2021, 02:44:03 PM
20 ppb ≠ 1 x 10-7 M.

Actually 1×10-7 M is 20 ppb (perhaps more like 21).
Title: Re: [itex]K_{sp} of PbCl_2[/itex]
Post by: Orcio_87 on April 11, 2021, 05:53:27 PM
@Borek Sorry, my error.

Now that I found that concentration of Cl- should be bigger than 13 M for Pb2+ smaller than 1 x 10-7 M (with K = [Pb][Cl]2 = 1,7 x 10-5).
Title: Re: [itex]K_{sp} of PbCl_2[/itex]
Post by: mjc123 on April 12, 2021, 09:05:38 AM
There seem to be different values out there in the literature. For example, on the wikipedia page for PbCl2, the quoted solubility and solubility product are inconsistent - 10.8 g/L implies Ksp = 2.85 x 10-4 M3.