Question

Match the complexes in Column-I with their hybridisation in Column-II.

Column-I     Column-II
A. \([ \mathrm{Ni(CO)_4} ]\)      1. \(dsp^2\)
B. \([ \mathrm{Ni(CN)_4} ]^{2-}\)      2. \(sp^3\)
C. \([ \mathrm{Ni(NH_3)_6} ]^{2+}\)      3. \(d^2sp^3\)
D. \([ \mathrm{Fe(CN)_6} ]^{3-}\)      4. \(sp^3d^2\)

• A. A-1, B-2, C-3, D-4
• B. A-2, B-1, C-4, D-3
• C. A-1, B-3, C-2, D-4
• D. A-2, B-3, C-1, D-4

Hint:

Strong field ligands → inner orbital (dsp$^2$, d$^2$sp$^3$); weak field → outer orbital (sp$^3$d$^2$).

Answer 1

The Correct Option is B

Concept: Hybridisation depends on:
•Nature of ligand (strong/weak field)
•Geometry (tetrahedral / square planar / octahedral)

Step 1: Analyze each complex (A) \([ \mathrm{Ni(CO)_4 ]\):}
CO is strong field ligand → tetrahedral complex \[ \Rightarrow sp^3 \] (B) \([ \mathrm{Ni(CN)_4 ]^{2-}\):}
CN\(^-\) strong field → square planar \[ \Rightarrow dsp^2 \] (C) \([ \mathrm{Ni(NH_3)_6 ]^{2+}\):}
NH\(_3\) weak/moderate field → octahedral outer orbital \[ \Rightarrow sp^3d^2 \] (D) \([ \mathrm{Fe(CN)_6 ]^{3-}\):}
CN\(^-\) strong field → inner orbital octahedral \[ \Rightarrow d^2sp^3 \]

Step 2: Matching \[ A \rightarrow 2,\quad B \rightarrow 1,\quad C \rightarrow 4,\quad D \rightarrow 3 \]