An excess of aqueous ammonia is added to three different flasks $$\text{F}_1$$, $$\text{F}_2$$ and $$\text{F}_3$$ containing aqueous solutions of $$\text{CuSO}_4$$, $$\text{Fe}_2(\text{SO}_4)_3$$ and $$\text{NiSO}_4$$ respectively. Which of the following is correct about this addition?
I. A precipitate will be formed in all three flasks.
II. Ammonia acts as a base as well as a ligand exchange reagent in $$\text{F}_1$$ and $$\text{F}_3$$.
III. A soluble complex of $$\text{NH}_3$$ and the metal ion is formed in $$\text{F}_1$$ and $$\text{F}_3$$.
IV. A precipitate will be formed only in $$\text{F}_2$$.