Mg(OH)2和MnCo3的Ksp数值相近,在Mg(OH)2和MnCo3两份饱和溶液中Mg2+和Mn2+浓度的关系?

Question

Mg(OH)2和MnCo3的Ksp数值相近,在Mg(OH)2和MnCo3两份饱和溶液中Mg2+和Mn2+浓度的关系?

Answer 1

Mg(OH)2 = Mg2+ + 2OH-
x 2x
x(2x)^2 = Ksp [Mg(OH)2 ]
x = { Ksp [Mg(OH)2 ] / 4}^1/3 = [Mg2+]
MnCO3 = Mn2+ + CO3 2-
y y
y = [Ksp(MnCO3) ] ^1/2 = [Mn2+]
因为二个Ksp接近,所以 4x^3 = y^2
即：4* [Mg2+] ^3 = [Mn2+] ^2
[Mg2+] < [Mn2+]