Which of the following species is not expected to be a ligand?

Options

A. `NO`
B. `NH_(4)^(+)`
C. `NH_(2)CH_(2)CH_(2)NH_(2)`
D. `CO`

Answer

B

Explanation

Ligand must donate a pair of electron or loosely held electron pair to metal and form a M-L bond.
e.g., `:overset(..)(N)=O, overset(..)(N)H_(2)CH_(2)CH_(2) overset(..)(N)H_(2), :CO`,
Among `overset(+)(N)H_(4)` does not have any pair of electron.
Hence `overset(+)(N)H_(4)` is not a ligand.