Question

Match the following:

List-I (Complexes)	List-II (Hybridisation and Shape)
(A) $[FeCl_6]^{3-}$	(I) $d^2sp^3$ and octahedral
(B) $[Fe(CN)_6]^{4-}$	(II) $sp^3d^2$ and octahedral
(C) $[Ni(CO)_4]$	(III) $dsp^2$ and square planar
(D) $[Ni(CN)_4]^{2-}$	(IV) $sp^3$ and tetrahedral

• A. (A)-(II), (B)-(I), (C)-(IV), (D)-(III)
• B. (A)-(I), (B)-(II), (C)-(III), (D)-(IV)
• C. (A)-(II), (B)-(I), (C)-(III), (D)-(IV)
• D. (A)-(I), (B)-(II), (C)-(IV), (D)-(III)

Answer 1

Answer: (A)

(A)-(II), (B)-(I), (C)-(IV), (D)-(III)

Answer 2

1. $[FeCl_6]^{3-}$: Fe$^{3+}$ ($3d^5$) with weak field $Cl^-$ ligands (CN=6) undergoes outer orbital hybridization $sp^3d^2$, resulting in an octahedral shape. (A)-(II)

2. $[Fe(CN)_6]^{4-}$: Fe$^{2+}$ ($3d^6$) with strong field $CN^-$ ligands (CN=6) undergoes inner orbital hybridization $d^2sp^3$, resulting in an octahedral shape. (B)-(I)

3. $[Ni(CO)_4]$: Ni$^0$ ($3d^8 4s^2$) with strong field CO ligands (CN=4) undergoes $sp^3$ hybridization, resulting in a tetrahedral shape. (C)-(IV)

4. $[Ni(CN)_4]^{2-}$: Ni$^{2+}$ ($3d^8$) with strong field $CN^-$ ligands (CN=4) undergoes inner orbital hybridization $dsp^2$, resulting in a square planar shape. (D)-(III)