Question

Ammonia forms the complex ion $ {{[Cu{{(N{{H}_{3}})}_{4}}]}^{2+}} $ with copper ions in the alkaline solutions but not in acidic solutions. What is the reason for it?

• A. In acidic solutions hydration protects copper ions
• B. In acidic solutions protons coordinate with ammonia molecules forming $ NH_{4}^{+} $ ions and $ N{{H}_{3}} $ molecules are not available
• C. In alkaline solutions insoluble $ Cu{{(OH)}_{2}} $ is precipitated which is soluble in excess of any alkali
• D. Copper hydroxide is an amphoteric substance

Answer 1

Answer: (B)

The pair of electron present with nitrogen will not be available to be donated as $ {{H}^{+}} $ will consume that one.