What are the equilibrium concentrations of the dissolved ions in a saturated solution of $Fe(OH)_2$ at 25°C?

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Answer 1 · 2017-08-03T21:32:30

We need $K_"sp"$ for $Fe(OH)_2$ .........

And we assess the equilibrium......

$Fe(OH)_2(s)rightleftharpoonsFe^(2+) + 2HO^-$

For which this site quotes $K_"sp"=8xx10^-16$ .

So we set the solubility of $Fe(OH)_2-=S$ .

And thus $K_"sp"=[Fe^(2+)][HO^-]^2=Sxx(2S)^2=4S^3$

And thus...... $S=""^(3)sqrt((8.0xx10^-16)/4)$

$=5.85xx10^-6*mol*L^-1$

And so $Fe^(2+)=5.85xx10^-6*mol*L^-1$

And $[HO^-]=1.17xx10^-5*mol*L^-1$

Can you work out the solubilities in $g*L^-1$ ?

What are the equilibrium concentrations of the dissolved ions in a saturated solution of Fe(OH)_2Fe(OH)_2 at 25°C?