Question

What is the molar solubility of PbBr₂ in water?

Answer 1

Equilibrium:

PbBr2(s) <--> Pb2+(aq) + 2 Br-(aq)

Ksp = 8.9 X 10^-6

8.9 X 10^-6= [Pb2+][Br-]^2

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in pure water,

let x = molar solubility of PbBr2.

[Pb2+] = x

[Br-] = 2x

8.9 X 10^-6 = x (2x)^2

8.9 X 10^-6= 4x^3

x = 0.013 M = molar solubility in pure wate

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