Question

A solution containing 0.17 M0.17 M each of F−, Cl−, CrO2−, and SO42− is titrated by a solution containing Pb2+Pb2+. Place the anions in the order in which they will precipitate. Consulting a table of Ksp values may be helpful.

Answer 1

To determine the order of precipitation of anions in the presence of Pb2+, Ksp values are considered. Typically, anions form precipitates from least to most soluble compounds, starting with lead chromate and ending with lead sulfate.

Step-by-step explanation:

The question is about the order of precipitation of anions in a solution when titrated with a Pb2+ solution. To determine the order of precipitation, we will need to consider the solubility product constants (Ksp) for each potential precipitate formed with Pb2+.

The Ksp values indicate how soluble a compound is in water; the lower the Ksp, the less soluble the compound, and thus, the more readily it precipitates. Based on typical Ksp values, lead sulfate (PbSO4) tends to have a higher Ksp than the other potential precipitates like lead fluoride (PbF2), lead chloride (PbCl2), and lead chromate (PbCrO4).

In general, the order of precipitation will start from the anion that forms the least soluble compound with Pb2+ to the most soluble one. Thus, without the specific Ksp values, typically, PbCrO4 would precipitate first, followed by PbF2, PbCl2, and lastly, PbSO4, assuming these are the potential precipitates and that they have typical Ksp values in the range of those commonly found in chemistry reference sources.

Answer 2

The order in which the anions will precipitate is F-, CrO4^2-, SO4^2-, Cl-.

Step-by-step explanation:

The order in which the anions will precipitate can be determined by comparing their solubility product constant (Ksp) values. The anion with the smallest Ksp value will precipitate first, followed by the anion with the second smallest value, and so on.

Using the provided information, we can compare the Ksp values of the anions:

• PbCrO4: Ksp = 1.4 × 10-8
• PbF2: Ksp = 3.9 × 10-8
• PbSO4: Ksp = 1.8 × 10-8
• PbCl2: Ksp = 1.7 × 10-5

Based on these Ksp values, the order in which the anions will precipitate is: F- < CrO42- < SO42- < Cl-.