Question

Solubility of pbf2 is 2.5×10^-3. What is the solubility

Answer 1

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Answer 2

Solubility of PbF2≈10−3M

Solubility of PbF2≈10−3M∴ Ksp=4S3=4×10−9

Solubility of PbF2≈10−3M∴ Ksp=4S3=4×10−9In 0.05M NaF we have 0.05M of F− ion contributed by NaF. IF the solubility of PbF2 in this solution is S M, then

Solubility of PbF2≈10−3M∴ Ksp=4S3=4×10−9In 0.05M NaF we have 0.05M of F− ion contributed by NaF. IF the solubility of PbF2 in this solution is S M, thentotal [F−]=[2S+0.05]M

∴ S[2S+0.05]2=4×10−9

∴ S[2S+0.05]2=4×10−9Assuming 2S<<0.05

∴ S[2S+0.05]2=4×10−9Assuming 2S<<0.05S×25×10−4=4×10−9

∴ S[2S+0.05]2=4×10−9Assuming 2S<<0.05S×25×10−4=4×10−9∴ S=0.16×10−5M ⇒ 1.6×10−6M

∴ S[2S+0.05]2=4×10−9Assuming 2S<<0.05S×25×10−4=4×10−9∴ S=0.16×10−5M ⇒ 1.6×10−6MWe observe that our approximation that 2S<<0.05 is justified.