Question

Calculate the concentration of sulfate ion when BaSO4 just begins to precipitate from a solution that is 0.0758M in Ba2+.

a) 3.79×10−4M
b) 5.07×10−4M
c) 7.58×10−5M
d) 1.52×10−4M

Answer 1

To calculate the concentration of sulfate ion when BaSO4 begins to precipitate from a solution with a given concentration of barium ions, we use the Ksp value and the given Ba2+ concentration. Dividing the Ksp by the concentration of Ba2+ gives us the concentration of SO42-. The calculation provided does not match the given answer choices, indicating a possible error.

Step-by-step explanation:

The question is asking us to calculate the concentration of sulfate ion, SO42-, when BaSO4 just begins to precipitate from a solution with a given concentration of barium ions, Ba2+.

To find this concentration, we use the solubility product constant, Ksp, for BaSO4. The Ksp is essentially the product of the concentrations of the ions at the point of saturation. According to the information given, the Ksp for BaSO4 at 25 degrees Celsius is 1.08 × 10-10. With a concentration of Ba2+ given as 0.0758 M, we can set up the equation:

Ksp = [Ba2+][SO42-] = 0.0758 × [SO42-]

By dividing the Ksp by the concentration of Ba2+, we find:

[SO42-] = Ksp / [Ba2+] = 1.08 × 10-10 / 0.0758 ≈ 1.42 × 10-9M

Since none of the provided answer choices match this calculation, it seems there may be a mistake either in the provided Ksp value or within the answer choices.