At 22 °C an excess amount of a generic metal hydroxide M(OH)2, is mixed with pure water.?
At 22 °C an excess amount of a generic metal hydroxide M(OH)2, is mixed with pure water. The resulting equilibrium solution has a pH of 10.21. What is the Ksp of the salt at 22 °C?
More Questions From This User See All
Answers & Comments
Verified answer
M(OH)2(s) <--> M²⁺ (aq) 2 OH⁻(aq)
Ksp = [M²⁺][OH⁻]²
1) Use the pH to get the pOH
14 – 10.21 = 3.79
2) Use the pOH to get the [OH⁻]
[OH⁻] = 10⁻pOH = 10^–3.79 = 1.622 x 10^–4
3) [M²⁺] is half the value of [OH⁻], therefore:
[M²⁺] = 1.622 x 10^–4 divided by 2 = 8.109 x 10^–5
4) Put values into Ksp expression
Ksp = (8.109 x 10^–5)(1.622 x 10^–4)²
Ksp = 2.13 x 10^–12