Question

Few drops of ammonium hydroxide is added to copper sulphate solution.
What would be the colour of the precipitate formed?

Answer 1

Answer:

I would be a dark blue colour..

Answer 2

Answer: Here is the answer...

Explanation:  Presumably, the hydrated copper sulfate (CuSO4–5 H2O) has been dissolved in water which places the copper ions (Cu2+) in solution. If a drop or two of ammonium hydroxide is added to this solution, initially, a small amount of copper (II) hydroxide will form by the following reaction.

Cu2+ + 2 OH- → Cu(OH)2(s)

This precipitate is a very pale blue color and will look white against the very dark blue of the surrounding solution. Depending on the amount of NH3 added, one may see only a flash of white precipitate form and then disappear.

As more ammonium hydroxide is added, the ammonia molecules (NH3) will force this precipitate into solution by reacting with copper ions to produce the very dark blue copper ammonia complex (tetraaminecopper(II) ion) by the following reaction:

Cu2+ + 4 NH3 → Cu(NH3)42+

Although the Cu(OH)2 dissolves as more ammonia is added, the ammonia does not actually react with the Cu(OH)2; it reacts with the Cu2+ that are in solution and this forces the Cu(OH)2 equilibrium to shift in the direction of its ions (by Le Chatelier’s Principle). This shift in equilibrium dissolves the Cu(OH)2 and forms the dark blue Cu(NH3)42+ complex ion.