JEE Main 2026 · 4 Apr · Shift 2 · Chemistry Q60

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ChemistrySingle correct+4 / -1Question 60 of 75

Consider the metal complexes $\ce{[Ni(en)3]^{2+}}$ (A), $\ce{[NiCl4]^{2-}}$ (B) and $\ce{[Ni(NH3)6]^{2+}}$ (C). Choose the CORRECT option by considering the number of unpaired electrons present in (A), (B) and (C) respectively and the order of frequency of absorption.

2, 2, 2 and (A) > (C) > (B)

0, 2, 0 and (A) > (C) > (B)

2, 2, 0 and (B) > (C) > (A)

2, 2, 2 and (C) > (A) > (B)

Answer and worked solution

Official answer: A

Unpaired electrons. Ni²⁺ is d⁸:

octahedral (A, C): $t_{2g}^6e_g^2$ , 2 unpaired;
tetrahedral $\ce{[NiCl4]^{2-}}$ : also 2.

So 2, 2, 2.

Absorption frequency ∝ Δ: en > NH₃ (octahedral), and the tetrahedral chloride complex has the smallest Δ. So (A) > (C) > (B).

(A)

Topics:Crystal field theory Magnetic properties and colour

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JEE Main 2026 · 4 Apr · Shift 2, Chemistry question 60