Question

Which one of the following is wrongly matched

• A. $[Ni(CO{)}_4]$ - neutral ligand
• B. $[Cu(N{H}_3{)}_4{]}^{2-}$ - square planar
• C. $[Co(en{)}_3{]}^{3+}$ - follows EAN rule
• D. $[Fe(CN{)}_6{]}^{3-}-s{p}^3{d}^2$

Answer 1

Answer: (D)

In ${\left[Cu{\left(N{H}_3\right)}_4\right]}^{2+},Cu$ is present as $C{u}^{2+}$

$C{u}^{2+}=[Ar]3d^{9}4s^0$



$(N{H}_3$ being a strong field ligand shifts one electron from $3d$ orbital to $4p$ orbital.)

(b) $In\left[Ni(CO{)}_4\right],CO$ is a neutral ligand.

(c) In [Fe(CN) ${{}_6]}^{3-}$, Fe is present as $F{e}^{3+}$.

$F{e}^{3+}=[Ar]3d^{5}4s^0$

${\left[Fe(CN{)}_6\right]}^{3-}=[Ar]$



Thus, its hybridisation is $d^{2}s{p}^3$ not $s{p}^3{d}^2,ie$, it is an inner orbital complex.

(d) ${\left[Co(en{)}_3\right]}^{3+}$ contains total 36 electrons, ie, follows EAN rule.