Question

Experiment 8 Solubility of lonic Precipitates Lead chloride is a slightly soluble salt. When lead chloride dissolves in pure water or an aqueous solution, the small quantity that dissolves completely ionizes and reaches equilibrium in a saturated solution, PbCl(s) ® Pb (aq) + 2Cl(aq) Kp = [Pb (C) (1) Lets be the molar solubility of lead chloride. In pure water, s = [Pb ) = (CH) / 2. In a solution containing Cl, a common ion to lead chloride, s = [Pb). In a solution containing Pb ions, another common ion to lead chloride, s = [CH] 2. The solubility of lead chloride and the common ion effect will be determined in this experiment. Procedure Solubility and Common Ion Effect Have three dry test tubes and three medicine droppers. One dropper will be used for 0.200 M Pb(NO), the other for 0.400 M HCI, and the last for deionized water. The three droppers must be approximately matched in the drop size. Ask instructor to help you select such droppers. To check the drop size, count drops of water added to a 10-ml graduated cylinder until reaching the scale of 3 mL or more. Then calculate the average mL per drop. Add 5 drops of Pb(NO3), 5 drops of HCI, and 5 drops of deionized water to one test tube. PbCl, precipitates. Tap the test tube to mix well. Then add water drop by drop. Stir by tapping the test tube at each addition, until the precipitate completely dissolves. Pour the solution into a dry 10-ml graduated cylinder to determine the final volume ve Calculate the equilibrium concentrations of Pb and Cl' and the molar solubility : [Pb = (drop) (mL/drop) (0.200 M)/v = S (CI) = (5 drop) (mL/drop) (0.400 M)/x = 2s Add 10 drops of Pb(NOx), and 5 drops of HCl to the second test tube. Mix by tapping. Then add water drop by drop until the PbCl, precipitate completely dissolves. Determine the final volume of the solution. In this case, [Pb) - (10 drop) (mL/drop) (0.200 M) [CI] = (5 drop) (mL/drop) (0.400 M)/v = 2s Add 5 drops of Pb(NO3), and 10 drops of HCl to the third test tube. Stir by tapping. Then add water drop by drop until all PbCl, precipitates just dissolve. Determine the final volume of the solution. In this case. [Pb°) - (5 drop) (mL./drop) (0.200 M)/v - S [CI] = (10 drop) (m/drop) (0.400 M)/V, Finally, calculate K by eq. 1.

Answer 1

* Saletion :- Salubility of Imic Peecipitates H. Salubility. Common Jon Effect Mixture 0.2MPb(No), aumecil up/ pbt2 cils KSP drops melly drops 10 Tulho is in pon increse and positive you sepeete and 3.1 10.322 1.29 10.645/0.535 5 . 13.9 0.512 11.024 (0.512 0.5361 10 line 10.204 11.632|08144 .513 Guestion :- 0 Ang - Poet - A does sarebility in watee Pheese in weatel negative ion ② Ang :- Common - ion effect in 1 The common - ion effect defels to in solubility the decleuse of an ionic Pleci- Pitate by the cedelition to the solution of a soluble compound with cm don in common with the plecipitate. This behaviour is a consequence of Le-chetelier's peinciple for the c@guilibrium cannerleaction of the jonic.