Given below are two statements: Statement I: $[\mathrm{Ni}(\mathrm{CN})_4]^{2-}$ is square planar and diamagnetic complex with $\mathrm{dsp}^{2}$ hybridization for Ni but $[\mathrm{Ni}(\mathrm{CO})_{4}]$ is tetrahedral, paramagnetic and with $\mathrm{sp}^{3}$-hybridization for Ni. Statement II: $[\mathrm{NiCl}_{4}]^{2-}$ and $[\mathrm{Ni}(\mathrm{CO})_{4}]$ both have same d-electron configuration have same geometry and are paramagnetic. In light the above statements, choose the correct answer form the options given below:

(B) Both Statement I and Statement II are false.

(A) Both Statement I and Statement II are true.

(C) Statement I is correct but statement II is false.

(D) Statement I is incorrect but statement II is true.

Coordination Compounds — JEE Main · 2022 · 28 Jun 2022 · Shift 1 Question with Solution

Given below are two statements:
Statement I:

[Ni (CN)_{4}]^{2 -}

is square planar and diamagnetic complex with

dsp^{2}

hybridization for Ni but

[Ni (CO)_{4}]

is tetrahedral, paramagnetic and with

sp^{3}

-hybridization for Ni.
Statement II:

[NiCl_{4}]^{2 -}

and

[Ni (CO)_{4}]

both have same d-electron configuration have same geometry and are paramagnetic.
In light the above statements, choose the correct answer form the options given below:

(A)Both Statement I and Statement II are true.
(B)Both Statement I and Statement II are false.✓ Correct
(C)Statement I is correct but statement II is false.
(D)Statement I is incorrect but statement II is true.

Answer: (B)

Solution

Statement I is FALSE:

$[Ni (CN)_{4}]^{2 -}$ : Ni is in +2 state ( $d^{8}$ ). CN⁻ is a strong-field ligand causing pairing. Geometry is square planar, hybridization $dsp^{2}$ , and it is diamagnetic (all electrons paired). ✓
$[Ni (CO)_{4}]$ : Ni is in 0 state ( $d^{10}$ ). CO is a strong-field ligand. Geometry is tetrahedral, hybridization $sp^{3}$ , but it is diamagnetic (not paramagnetic, since $d^{10}$ has no unpaired electrons). ✗

Statement II is FALSE:

$[NiCl_{4}]^{2 -}$ : Ni is in +2 state ( $d^{8}$ ). Cl⁻ is a weak-field ligand, no pairing. Geometry is tetrahedral, hybridization $sp^{3}$ , and it is paramagnetic (2 unpaired electrons).
$[Ni (CO)_{4}]$ : Ni is in 0 state ( $d^{10}$ ). Geometry is tetrahedral, hybridization $sp^{3}$ , and it is diamagnetic.
They do NOT have the same d-electron configuration ( $d^{8}$ vs. $d^{10}$ ), NOT the same magnetic property (paramagnetic vs. diamagnetic). ✗

Both statements are false.

JEE Main · 2022 · 28 Jun 2022 · Shift 1 · Single correct option

JEE Main · 2022 · 28 Jun 2022 · Shift 1 · Coordination Compounds

Solution

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