JEE Main 2026 — Jan 22, Shift 2 — Chemistry solution

JEE Main2026Jan 22, Shift 2Chemistry

$[N i (P P h_{3})_{2} C l_{2}]$ is a paramagnetic complex. Identify the INCORRECT statements about this complex.

A. The complex exhibits geometrical isomerism.

B. The complex is white in colour.

C. The calculated spin-only magnetic moment of the complex is 2.84 BM.

D. The calculated CFSE (Crystal Field Stabilization Energy) of Ni in this complex is $- 0.8 Δ_{0}$ .

E. The geometrical arrangement of ligands in this complex is similar to that in $N i (C O)_{4}$ .

Choose the correct answer from the options given below :

A
A and B only
B
A, B and D only
C
C and D only
D
C, D and E only

Solution

$N i^{2 +}$ ( $3 d^{8}$ ) with bulky $P P h_{3}$ ligands and paramagnetism implies a tetrahedral geometry (two unpaired electrons in the $t_{2}$ set).

A) Tetrahedral complexes do not show geometrical isomerism — so this statement is INCORRECT.

B) Tetrahedral $N i (I I)$ complexes are typically coloured (often blue/green), not white — INCORRECT.

C) Spin-only moment for 2 unpaired electrons: $μ = 2 (2 + 2) = 8 = 2.84$ BM — correct.

D) CFSE for tetrahedral $d^{8}$ filling ( $e^{4} t_{2}^{4}$ ): $C F S E = 4 (- 0.6 Δ_{t}) + 4 (0.4 Δ_{t}) = - 0.8 Δ_{t}$ (not $Δ_{0}$ ) — INCORRECT due to the subscript.

E) $N i (C O)_{4}$ is tetrahedral, same as this complex — correct.

Incorrect statements: A, B and D.

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