Preparing some copper(I) ions for a reduction. Chemistry is always fun when it’s possible to work on a lit larger scale.
The deep blue color of the tetraamminecopper(II) ions is quite characteristic. If some copper(II) ions are present in a solution and ammonia is added, the solution will turn into deep blue from the original faint blue color.
What happens here? This: CuSO4(aq) + 4 NH3(aq) —> [Cu(NH3)4]SO4(aq)