Question

Ammonia forms the complex `[Cu(NH_3)_4]^(2+)` with copper ions in alkaline solution but not in acid solution. The reasons for it is:
A. In acidic solution hydration protects `Cu^(2+)` ion
B. In acidic solution proton coordinates with ammonia molecules to form `NH_(4)^(+)` ions and `NH_(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 amphorteric substance.

Answer 1

Correct Answer - D
In acidic solution proton coordinates with ammonia molecules to form `NH_(4)^(+)` ions and `NH_(3)` molecules are not aveilable for complex show formation .