What would be observed when aqueous ammonia is added in drops and then in excess to a solution of copper(II) ions?

When aqueous ammonia is added in drops to a solution of copper(II) ions, a pale blue precipitate is formed. This is due to the formation of a complex ion known as tetraamminecopper(II) [Cu(NH3)4]2+. This complex ion has a blue color and is responsible for the color change observed in the solution. If more aqueous ammonia is added to the solution, the blue precipitate dissolves due to the formation of a soluble complex ion known as pentamminecopper(II) [Cu(NH3)5]2+. This solution will appear deep blue in color. Therefore, when excess aqueous ammonia is added to a solution of copper(II) ions, a deep blue solution of pentamminecopper(II) complex ion is formed, and there will be no precipitate. It is important to note that the color changes observed are due to the formation of complex ions and not due to the formation of a new substance.