Find the value of the solubility product ksp for a saturated solution of mercury bromide, hgbr2, using the solubility of mercury bromide. the solubility, s, of mercury bromide is 2.66×10−7 m. express your answer numerically to three significant figures.

When the reaction equation is:

HgBr2(s) ↔ Hg2+(aq)   +   2Br-(aq)

So Ksp expression = [Hg2+] [Br-]^2

assume the solubility S = X = 2.66 x 10^-7 M 

and from the reaction equation :

we can see that [Hg2+] = X

and the [Br-] = 2 X

so by substitution in Ksp formula will can get the Ksp value:

∴ Ksp = X * (2X)^2

       = 2.66 x 10^-7 * (2*2.66 x 10^-7)^2

       = 7.53 x 10^-20