In preparation of Fe(OH)_3 from FeCl_3 first NH_4Cl is added and than NH_4OH is added ? Why ?

In preparation of Fe(OH)_3 from FeCl_3 first NH_4Cl is added and than

1.	In preparation of Fe(OH)_3 from FeCl_3 first NH_4Cl is added and than NH_4OH is added ? Why ?
Answer» SOLUTION : Due to common ION effect of `NH_4^+`its CONCENTRATION increases so the REACTION mens in reverse direction and `OH^-` remain limited to `Fe_((aq))^(+)`and from `Fe(OH)_3`.