Question

The ksp of aluminum hydroxide is 5.6e-17. What is the concentration of hydroxide in a saturated solution?

For the answer I got
[AlOH] <=> [Al] [OH]^2
5.6e-17 x 3x
5.6e-17 = 3x^4
x = 6.6e-5

Is this right? I'm not sure about 3x^4 part...

Answer 1

yep its right

Answer 2

No it isn't right.
Al(OH)3 ==> Al^3+ + 3OH^-
Ksp = (Al^3+)(OH^-) = 5.6E-17
(Al^3+) = x
(OH^-) = 3x
(x)(3x)^3 = 5.6E-17
27x^4 = 5.6E-17
Solve for x, then multiply that by 3 for OH^-

Answer 3

Thank you !!