FeCl3(aq) ==> Fe^3+(aq) + 3Cl^-(aq)
NaOH(aq) ==> Na^+(aq) + OH^-(aq)
mols FeCl3 = grams/molar mass
mols NaOH = grams/molar mass
(FeCl3) = mols/total L
(NaOH) = mols/total L.
The reaction is
FeCl3(aq) + 3NaOH(aq) ==> 3NaCl(aq) + Fe(OH)3(s)
The remainder of this problem is a limiting reagent, a Ksp, and a common ion effect all rolled into one.