Question

The salts X(NO₃)₂ and Y(NO3)₂ (where X+2 and Y+2 are metal ions) are dissolved in water to give a solution which is 0.1 M in each of them. Using the Ksp values listed below, decide which aqueous reagent, if any, will definitely precipitate X+ before precipitating Y+ from solution.

Given Ksp values:

XCl₂, 1 x 10⁻⁵ YCl₂, 1 x 10⁻¹⁰ X(OH)₂, 1 x 10⁻¹⁰ Y(OH)₂, 1 x 10⁻⁵

A)1M NH3

B)1M HCl

C)1M HNO₃

D) 1M NaCl

E) None of the above reagents will accomplish the precipitation

Answer 1

1M NaCl will precipitate X+ before Y+ because it provides Cl- ions that will form a precipitate with X2+ at a lower concentration than Y2+, considering XCl2 has a higher solubility product (Ksp) than YCl2.

option d is the correct

Step-by-step explanation:

To determine which aqueous reagent will precipitate X+ before Y+ from a solution that is 0.1 M in X(NO3)2 and Y(NO3)2, we should look for a reagent that could form a precipitate with either X2+ or Y2+ ions based on the provided Ksp values for XCl2 and YCl2, as well as X(OH)2 and Y(OH)2.

Considering the given Ksp values, we can conclude that:

• XCl2: Ksp = 1 x 10-5
• YCl2: Ksp = 1 x 10-10
• X(OH)2: Ksp = 1 x 10-10
• Y(OH)2: Ksp = 1 x 10-5

Given these Ksp values, we are looking for a reagent that would lead to the formation of a chloride or hydroxide with X+ at a lower concentration than Y+. 1M NaCl would provide Cl- ions and thus, based on the Ksp values, it would precipitate X+ because XCl2 has a higher Ksp than YCl2. The other options, such as NH3, HCl, HNO3, would either not provide the anions needed to form a precipitate or would affect both cations similarly and not lead to a selective precipitation.