A generic salt, AB2 , has a molar mass of 191 g/mol and a solubility of 6.60 g/L at 25 °C.What is the 𝐾sp of this salt at 25 °C?

Answer 1

The solubility of the salt AB2 is given as 6.60 g/L at 25°C. The molar mass of AB2 is 191 g/mol. To find the 𝐾sp of the salt at 25°C, we need to use the solubility product expression and substitute the appropriate values:

𝐾sp = [A2+][B-]

The balanced chemical equation for the dissociation of AB2 is:

AB2(s) ⇌ A2+(aq) + 2B-(aq)

We can see from the equation that the concentration of A2+ is the same as the concentration of AB2 that has dissolved. Let's call the concentration of AB2 that has dissolved x (in mol/L). Then the concentration of A2+ is also x. The concentration of B- is 2x, since each unit of AB2 that dissolves releases two units of B- ions.

The molar solubility of AB2 (in mol/L) can be calculated by dividing the solubility (in g/L) by the molar mass (in g/mol):

mol/L = (g/L) / (g/mol) = 6.60 / 191 = 0.0345

The concentration of A2+ is also 0.0345 M, and the concentration of B- is 2(0.0345) = 0.0690 M.

Now we can substitute these values into the solubility product expression:

𝐾sp = [A2+][B-] = (0.0345)(0.0690)^2

𝐾sp = 1.44 × 10^-4

Therefore, the 𝐾sp of AB2 at 25°C is 1.44 × 10^-4.