question_answer

Ammonia forms the complex ion \[{{[Cu{{(N{{H}_{3}})}_{4}}]}^{2+}}\]with copper ions in alkaline solution but not in acidic solution. The probable reason for this is

A)  In acidic solution, hydration protects \[C{{u}^{2+}}\] ion

B)  In acidic solution, proton coordinates with ammonia molecules to from \[NH_{4}^{+}\] ions and \[N{{H}_{3}}\] Molecules are not available

C)  In alkaline solution, insoluble \[Cu{{\left( OH \right)}_{2}}\] is precipitated which is soluble in excess of any alkali.

D)  Copper hydroxide is an amphoteric substance.