Ammonia forms the complex `[Cu(NH_(3))_(4)]^(2+)` with copper ion in alkaline solution but not in acidic solution. This is due to the reason that :

Options

A. in alkaline solution insoluble `Cu(OH)_(2)` is precipitated which is soluble in excess of any alkali
B. `Cu(OH)_(2)` is amphoteric
C. in acidic solution hydration protects `Cu^(2+)` ion
D. in acidic solution, proton coordinates with `NH_(3)` forming `NH_(4)^(+)` ion and `NH_(3)` is not available

Answer

D

Explanation

It is the correct answer.
`overset(..)(N)H_(3) + underset(("Acid"))(H^(+)) rarr NH_(4)^(+)`
Lone pair is not available for co-ordination with `Cu^(2+)` ion