Would someone please tell me if my leg work and logic behind this question is correct?
Q: 2.20g of solid NaOH are added to 250 mL of 0.10 M FeCl2 solution. Given the Ksp for Fe(OH)2 is 1.6 x 10-14 calculate:
a. the weight of Fe(OH)2 formed
b. the molar concentration of Fe2+ in the final solution.
I have done all the leg work, which makes perfect sense to me, unfortunately I am extremely worried that I am wrong.
Would you chemists please review my work and tell me if I am on the correct path?
a. weight of Fe(OH)2 formed
g FeCl2 ----> mol FeCl2 ----> mol fe(OH)2 ----> g Fe(OH)2
2.20g NaOH x 1mol/41.01 gNaOH x 1 mol Fe(OH)2/1 mol NaOH x 73.87 g/1 mol Fe(OH)2
= 3.99 g FeOH2- is what I would propose is the weight of Fe(OH)2 formed. I calculated this using the stoichiometric ratios.
b. the molar concentraiton of Fe2+ in the final solution
Fe(OH)2 <----------> Fe2+ 2(OH-)
INITIAL O O
CHANGE +s +2s
EQUIL S 2S
Ksp = [Fe][OH]2
Ksp = [ S][2S]2
Ksp = [ S] [4S2]
1.6 x 10-14 = 4s3 (divide both sides by four, then cube root right side)
1.59 x 10-5 = s
Therefore the molar concentration of Fe2+ in the final solution would be 1.59 x 10-5
Any help, direction and time would be deeply appreciated!!