The solubility of lead (II) Iodate, Pb(IO_3)_2Pb(IO3)2, is 0.76 g/L at 25*C. How do you calculate the Value of Ksp at this same temperature?

1 Answer
Jun 7, 2016

K_(sp)Ksp Pb(IO_3)_2Pb(IO3)2 == ????

Explanation:

We can represent the solubility of Pb(IO_3)_2Pb(IO3)2 as:

Pb(IO_3)_2(s) rightleftharpoons Pb^(2+) + 2IO_3^-Pb(IO3)2(s)Pb2++2IO3

K_(sp)Ksp == [Pb^(2+)][IO_3^-]^2[Pb2+][IO3]2

And if we let S="solubility of lead iodate"S=solubility of lead iodate, then,

K_(sp)Ksp == (S)(2S)^2(S)(2S)2 == 4S^34S3.

So now we work out the solubility of Pb(IO_3)_2Pb(IO3)2.

We are given S_("mass")=0.76*g*L^-1Smass=0.76gL1

S_("molar")=(0.76*g)/(557.00*g*mol^-1)xx1/(1*L)Smolar=0.76g557.00gmol1×11L

== 1.37xx10^-3*mol*L^-11.37×103molL1

And thus K_(sp)=4xx(1.37xx10^-3)^3Ksp=4×(1.37×103)3 == ????

Lead iodate is thus quite an insoluble beast.

See here and and here for other examples.