Question

On reacting copper hydroxide with an excess of ammonium hydroxide and ammonium sulphate, we get a deep blue solution. The formula of the solution is :

• A. $\left[Cu\right(N{H}_3{)}_3]S{O}_4$
• B. $\left[Cu\right(N{H}_3{)}_4]S{O}_3$
• C. $\left[Cu\right(N{H}_3{)}_4]S{O}_4$
• D. $\left[Cu\right(N{H}_3{)}_2]S{O}_4$

Answer 1

Answer: (C)

$\left[Cu\right(N{H}_3{)}_4]S{O}_4$

$CuC{l}_2+(N{H}_4{)}_{2}S{O}_4+2N{H}_{4}OH⟶4H_{2}O+[Cu\left(N{H}_3{)}_4\right]S{O}_4$

$\left[Cu\right(N{H}_3{)}_4]S{O}_4$ is a deep blue solution and the reaction is a characteristic property of $C{u}^{2+}$.