Question

Ammonia forms the complex ion [Cu(NH₃)₄]²⁺ with copper ions in alkaline solutions but not in acidic solutions. What is the reason for it ? (a) In acidic solutions protons coordinate with ammonia molecules forming $NH_4^+$ ions and NH₃ molecules are not available(b) In alkaline solutions insoluble Cu(OH)₂ is precipitated which is soluble in excess of any alkali(c) Copper hydroxide is an amphoteric substance(d) In acidic solutions hydration protects copper ions

Answer 1

B.) In alkaline solutions insoluble Cu(OH)₂ is precipitated which is soluble in excess of any alkali