Which best describes what happens when 50 mL of 0.0010M CaCl2 is added to 50 mL of 0.010M Na2SO4? (The Ksp of CaSO4 = 2.4 * 10-5.)

The solution will be at equilibrium.

CaSO4 will precipitate out of solution

No precipitation will occur.

When the solutions are diluted in half:

So [ Ca+2] = 0.001/2 = 0.0005 M

[SO4-2] = 0.01/2 = 0.005

when Q = [Ca2+][SO4-2]

so by substitution:

Q = 0.0005*0.005 = 2.5x10^-6

by comparing with Ksp value

So when Q < Ksp

∴ the answer is no precipitation will occur, as the solution is unsaturated.