Explanation

(c)
In $\left\lbrack Cu\left( NH_{3} \right)_{4} \right\rbrack^{2 +},\ Cu$ is present as $Cu^{2 +}$
$Cu^{2 +} = \lbrack Ar\rbrack 3d^{9}4s^{0}$
$\left\lbrack Cu\left( NH_{3} \right)_{4} \right\rbrack^{2 +} = \lbrack Ar\rbrack$
[image:9_image232.emf]
($NH_{3}$ being a strong field ligand shifts one electron from 3d-orbital to 4p-orbital.)
In $\left\lbrack Ni(CO)_{4} \right\rbrack,CO\$ is a neutral ligand
In $\left\lbrack Fe(CN)_{6} \right\rbrack^{3 -},\ Fe\$ is present as $Fe^{3 +}.$
$Fe^{3 +} = \lbrack Ar\rbrack 3d^{5}4s^{0}$
$\left\lbrack Fe(CN)_{6} \right\rbrack^{3 -} = \lbrack Ar\rbrack$
[image:9_image233.emf]
Thus, its hybridization is $d^{2}sp^{3}$ not $sp^{3}d^{2}$, i.e., it is an inner orbital complex.
$\left\lbrack Co(en)_{3} \right\rbrack^{3 +}contains\ total\ 36\ electrons,\ i.e.,$ follows EAN rule.