For each reaction,which ion in the precipitate was responsible for the color

Question

1-reaction of Sodium Hydroxide and Copper(II)Sulfate

2-reaction of Sodium Sulfate and Barium Chloride.

3-reaction of Sodium Hydroxide and Iron(III)Sulfate.

4-reaction of Sodium Hydroxide and Nickel(II)chloride.

5-reaction of Potassium Iodide and lead (II)Nitrate.

6-reaction of Sodium Hydroxide and Iron(II)Sulfate.

Answer 1

Cu, Ba, Fe, Ni, I, Fe