Difficult Chemistry question...precipitation?

Question

So you are given (Fe2(OH) (*Ksp = 5 x 10^-17) and it has a water solubility of 2.3 x 10^-6

a) What is the Ksp expression for OH-?

b) Will a precipitation form if 5 mL of .03 M of NaOH is added to 100mL of 0.125M Fe(NO3)2?

c) How many milligrams of FeOH are neccessary to prepare a saturated solution of FeOH2?

d) How many milligrams of FeOH can be dissolved in 1 Liter of 1.5 M FeNO3 solution?

e) Fe(OH) can be dissolved in an aqueous solution of CN-...It forms Fe(CN)6^-4

Kf= 4 x 10^45

Calculate the molar solubility in a 1M CN- solution?

Thanks so much for your help!

Answer 1

a) Hydroxide

b) Yes

c) Duno

d) use formula v = n X c

e) dunno