The dark blue colour of the solution formed when excess of ammonia is added to a solution of copper (II) sulphate is due to the presence of the ion

Options

(a) [Cu(OH)₄(H₂O)₂]²⁻
(b) [Cu(H₂O)₆]²⁺
(c) [Cu(NH₄)₂(H₂O)₄]⁴⁺
(d) [Cu(NH₃)₄(H₂O₂)]²⁺

Correct Answer:

[Cu(NH₃)₄(H₂O₂)]²⁺

Explanation:

when excess of ammonia is added to a solution of copper (II) sulphate, then the complex compound, [Cu(NH₃)₄(H₂O₂)]SO₄ is formed which causes the formation of deep blue colour.