A generic metal thiocyanate, M(SCN)2, has a Ksp value of 2.00×10−5. Calculate the molar solubility of the metal thiocyanate in 0.421 M KSCN. Express your answer numerically in units of mM to 4 decimal places.

Respuesta :

Answer:

The molar solubility of the metal thiocyanate is [tex]1.127\times 10^{-4} M[/tex].

Explanation:

Concentration of potassium thiocyanate = 0.421 M

Concentration of thiocyanate ion =[tex][SCN^-]= 0.421 M[/tex]

Concentration of metal ion =[tex][M^{2+}]= ?[/tex]

The solubility product of metal thiocyanate = [tex]K_{sp}=2.00\times 10^{-5}[/tex]

[tex]M(SCN)_2\rightleftharpoons M^{2+}+2SCN^-[/tex]

                          S          2S

At equilbrium

                         S       (2S+0.421)

The expression of solubility product is given by :

[tex]K_{sp}=[M^{2+}]\times [SCN^-]^2[/tex]

[tex]2.00\times 10^{-5}=S\times (2S+0.421)^2[/tex]

Solving for S:

[tex]S = 1.128\times 10^{-4} M[/tex]

[tex][M^{2+}]=\frac{2.00\times 10^{-5}}{(0.421 M)^2}=1.127\times 10^{-4} M[/tex]

The molar solubility of the metal thiocyanate is [tex]1.127\times 10^{-4} M[/tex].