Chemistry Solubility Math Question 11

Question

Determine the solubility of aluminum hydroxide, Al(OH)₃, in a buffer solution at a pH of 7. 

K_sp = 3.7E-15

Answer 1

Al(OH)₃(s) <==> Al³⁺(aq) + 3OH-(aq)

Ksp = 3.7x10^-15 = [Al³⁺][OH-]³

Let x = [Al³⁺], and then [OH-] = 3x

3.7x10^-15 = [x][3x]³

27x⁴ = 3.7x10^-15

x4 = 1.37x10^-16

x = 1.08x10^-4 M