Which of the following solutions will not form a precipitate when added to 10 mL of 0.10 M KOH? (LO 4.10, 4.11) (a) 10 mL of 0.10 NH4Cl (b) 10 mL of 0.10 M PbSO4 (c) 10 mL of 0.10 M Fe(NO3)3 (d) 10 mL of 0.10 M AgCH3CO2

Verified step by step guidance

1. Identify the ions present in each solution when mixed with KOH: NH4Cl provides NH4^+ and Cl^-, PbSO4 provides Pb^2+ and SO4^2-, Fe(NO3)3 provides Fe^3+ and NO3^-, AgCH3CO2 provides Ag^+ and CH3CO2^-.
2. Consider the solubility rules to determine if any of the ions will form an insoluble compound with OH^- from KOH.
3. Recall that most hydroxides are insoluble except those of alkali metals and Ba^2+, Sr^2+, and Ca^2+ to some extent.
4. Evaluate each combination: NH4^+ with OH^- forms NH3 and H2O, which is soluble; Pb^2+ with OH^- forms Pb(OH)2, which is insoluble; Fe^3+ with OH^- forms Fe(OH)3, which is insoluble; Ag^+ with OH^- forms AgOH, which is insoluble.
5. Determine which solution does not form a precipitate: NH4Cl does not form a precipitate with KOH, as NH4OH is soluble.

Key Concepts

Precipitation Reactions

Precipitation reactions occur when two soluble ionic compounds react in solution to form an insoluble compound, known as a precipitate. The solubility of the resulting compounds can be predicted using solubility rules, which state that certain combinations of ions will not dissolve in water. Understanding these rules is essential for determining whether a precipitate will form when mixing solutions.

Solubility Product Constant (Ksp)

The solubility product constant (Ksp) is a numerical value that represents the equilibrium between a solid and its ions in a saturated solution. It helps predict whether a precipitate will form based on the concentrations of the ions in solution. If the product of the ion concentrations exceeds the Ksp, a precipitate will form; if not, the ions remain in solution.

Common Ion Effect

The common ion effect refers to the decrease in solubility of an ionic compound when a common ion is added to the solution. This phenomenon is important in precipitation reactions, as the presence of a common ion can shift the equilibrium, potentially preventing the formation of a precipitate. Recognizing the common ions in the solutions being mixed is crucial for predicting the outcome of the reaction.