Question

Addition of strong ammonium hydroxide solution into cupric solution gives deep blue solution why?

Answer 1

When aqueous ammonia, NH3 (aq), is added to a solution of copper sulfate, CuSO4, first a precipitate of copper hydroxide, Cu(OH)2, begins to form. When more ammonia is added, the precipitate dissolves and the solution turns from a light blue to a deep royal blue indicating the presence of Cu(NH3)4^2+. Which of the following statements best explains this observation?

b) Copper ions form a complex ion with ammonia, Cu(NH3)4^2+, which removes Cu^2+ from the solubility equilibrium, causing the copper hydroxide to dissolve.

c) With the increase in volume of the solution from the added ammonia, the concentration of copper ions and hydroxide ions decreases enough to make