Synthetic pathways to produce the provided complex

[Faiq]

Question
Describe the color changes that occur when $NH_{3(aq)}$ is gradually added, with stirring to $[CuCl_4]^{2-}_{(aq)}$ until the $NH_{3(aq)}$ is in excess.
Identify the three compounds or ions responsible for the new colors.

Now the marking scheme shows that somehow $[Cu(H_2O)_6]^{2+}_{(aq)}$,$Cu(OH)_{2(aq)}$ and $[Cu(NH_3)_4(H_2O)_2]^{2+}_{(aq)}$ gets produced.
The only reaction I am taught concerning $[CuCl_4]^{2-}_{(aq)}$ and $NH_{3(aq)}$ is
$[CuCl_4]^{2-}_{(aq)}$ + $NH_{3(aq)}$ (in excess) ----->$[Cu(NH_3)_4(H_2O)_2]^{2+}_{(aq)}$

Can someone tell me a reaction pathway in which all these three ions are achieved?

 

[Nino MMP]

AnswerThe reaction pathway for the color changes when $NH_{3(aq)}$ is gradually added to $[CuCl_4]^{2-}_{(aq)}$ until the $NH_{3(aq)}$ is in excess is as follows:1. $[CuCl_4]^{2-}_{(aq)}$ + 2H_2O <=> $[Cu(H_2O)_6]^{2+}_{(aq)}$ + 4Cl^-2. $[Cu(H_2O)_6]^{2+}_{(aq)}$ + 2NH_3 <=> $[Cu(NH_3)_4(H_2O)_2]^{2+}_{(aq)}$ + 2H_2O3. $[Cu(H_2O)_6]^{2+}_{(aq)}$ + OH^- <=> $Cu(OH)_{2(aq)}$ + 6H_2OThe three compounds/ions responsible for the new colors are $[Cu(H_2O)_6]^{2+}_{(aq)}$, $Cu(OH)_{2(aq)}$ and $[Cu(NH_3)_4(H_2O)_2]^{2+}_{(aq)}$.