Question

At room temperature, you are given a litre of a solution of PbCl_2(aq)inwhich there is excess PbCl_2(s)i.e. a saturated solution. State and explain the effect of the following on the concentration of the Pb²⁺ ions in the solution? [Remember to use ideas on equilibrium, Le Chatelier's Principle, etc. in your answer]

1. Adding more PbCl₂ solid
2. Adding NaClsolid
3. Adding 500 ml of water, assuming there will still be excess solid afterwards.
4. Heating the solution to 35 ⁰C assuming the solubility is endothermic

Answer 1

The equithe equilibrium for dissolution of obly is pbu, (8 = P62109.) + 241" (eq.) (1) Adding more polly :- In saturated solution pblz is dissowed to the maximum capacity and the solubility product Kop is given by - Kep = [Pb2+ ] [-]? In this expression abu, (s) does not feature, so it will not have any effect on concentration of Pb2+ in solution. (1) when wall is added it increases the comentration of u in soution and as Ksp is a fixed quantity some of Pb2+ is precipitated out in form of pet obl so the concentration of Pb2+ will decrease (iii) when we add soome of water volume of solution increases, concentration of Pb2+ decreases, however as there is excess solid some of pbed will dissowe until the solution becomes saturated. How In saturated solution concentration of pbat remains fixed according to ksp . so if there is still solid left adding water will not have any effect on concentration of Pb²+ liv ! $ As solubility is endothermie increasing temperature will enhance solubility according to Le-chateliers principle. So concentration of Port will increase.