Question

Write a chemical equation for the below reaction:

Ammonium Hydroxide is first added in a small quantity and then in excess to a solution of copper sulfate.

Answer 1

1. On adding Ammonium hydroxide (${\mathrm{NH}}_4\mathrm{OH}$) in a small amount in a solution of Copper sulfate, Ammonium sulfate (${\mathit{\left(}N{H}_{\mathit{4}}\mathit{\right)}}_{\mathit{2}}S{O}_4$) and Copper hydroxide ($\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$) is formed which is blue in color.
2. Copper hydroxide of blue color dissolves in excess of ammonium hydroxide and forms a deep blue solution.
3. The reaction is given below:

$$\begin{gathered} {\mathrm{CuSO}}_4+2{\mathrm{NH}}_4\mathrm{OH}\to \mathrm{Cu}(\mathrm{OH}{)}_2+{\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4 \\ \mathrm{Cu}(\mathrm{OH}{)}_2+4{\mathrm{NH}}_4\mathrm{OH}\to \mathrm{Cu}{\left({\mathrm{NH}}_3\right)}_4(\mathrm{OH}{)}_2+4{\mathrm{H}}_2\mathrm{O} \end{gathered}$$