At a certain temperature, the solubility of barium chromate (BaCrO_4BaCrO4) is 1.8 x 10^-51.8x105 mol/L. What is the Ksp value at this temperature?

1 Answer
Oct 27, 2016

K_(sp)Ksp == [Ba^(2+)][CrO_4^(2-)][Ba2+][CrO24] == (1.8xx10^-5)^2(1.8×105)2

Explanation:

We write the solubility expression in this way:

BaCrO_4(s) rightleftharpoons Ba^(2+) + CrO_4^(2-)BaCrO4(s)Ba2++CrO24

Now K_(sp)Ksp == [Ba^(2+)][CrO_4^(2-)][Ba2+][CrO24] == (1.8xx10^-5)^2(1.8×105)2 == 3.24xx10^-10.3.24×1010.

Why do we square this value? We were quoted the solubility of barium chromate. Because the solubility represents the concentrations of chromate ion and barium ion.