Question

Choose the correct option regarding the following complex compound which follows $\left(F\right)$ and does not follow $\left(NF\right)$ the Sidgwick EAN rule:
(I) $\left[\right(P{h}_{3}P{)}_{3}PdC{l}_{2}PdC{l}_2]$ (II) $\left[NiBrCl\right(en\left)\right]$ (III) $N{a}_4\left[Fe\right(CN{)}_{5}NOS]$ (IV) $Cr\left(CO{)}_3\right(NO{)}_2$.

• A. (I) NF (II) NF (III) NF (IV) NF
• B. (I) F (II) F (III) NF (IV) F
• C. (I) NF (II) NF (III) F (IV) F
• D. (I) NF (II) NF (III) F (IV) NF

Answer 1

The correct option is C (I) NF (II) NF (III) F (IV) F

$EAN=Z-X+Y$
Z$=$Atomic number of the metal
X$=$Number of electrons lost during the formation of the metal ion from its atom
Y$=$Number of electrons donated by the ligands

(i) For $\left[P{h}_{3}P{)}_{2}PdC{l}_2\right]$ AN of $Pd=46-2+4\times 2=52$.
The atomic number of xnon is 54.
Hence, it does not follows EAN.

(ii) For $\left[NiBrCl\right(en\left)\right]$, EAN of $Ni=28-2+8=34$.
The atomic number of krypton is 36.
Hence, it does not follows EAN.

(iii) For $N{a}_4\left[Fe\right(CN{)}_{5}NOS]$, EAN of $Fe=26-2+5\times 2+2=36$.
This is equal to the atomic number of krypton.
Hence, it follows EAN.

(iv) For $Cr\left(CO{)}_3\right(NO{)}_2$, EAN of $Cr=24-0+3\times 2+3\times 2=36\left[Kr\right]$.
This is equal to the atomic number of krypton.
Hence, it follows EAN.