What is the maximum mass of KCl that can be added to1.0 L of a 0.010 M lead(II) chloride solution without causing any?

2016-04-27 8:07 am

precipitation of lead(II) chloride? Assume that addition of KCl does not affect the solution volume. For lead(II) chloride, Ksp = 1.6 x 10-5 .

回答 (1)

戇戇居士

2016-04-27 8:28 am

✔ 最佳答案

Assume that there is no change in volume when KCl is added.

PbCl₂(s) ⇌ Pb²⁺(aq) + 2Cl⁻(aq)

When maximum mass of KCl is added :
[Pb²⁺] [Cl⁻]² = Ksp
(0.010) × [Cl⁻]² = 1.6 × 10⁻⁵
[Cl⁻]² = 1.6 × 10⁻³
[Cl⁻] = 0.040 mol/L

Maximum number of moles of KCl
= Maximum number of moles of Cl⁻
= [Cl⁻] × (Volume of the solution)
= (0.040 mol/L) × (1.0 L)
= 0.040 mol

Maximum mass of KCl
= (Maximum number of moles of KCl) × (Molar mass of KCl)
= (0.040 mol) × [(39.01 + 35.45) g/mol]
= 2.98 g

👍 1 👎 0