The correct increasing order of spin-only magnetic moment values of the complex ions [ MnBr 4 ] 2- ( A ), [ Cu ( H 2 O ) 6 ] 2+ ( B ), [ Ni ( CN 4 ) ] 2- ( C ) and [ Ni ( H 2 O ) 6 ] 2+ ( D ) is:

Chemistry · Coordination Compounds

JEE Main 2026 — 28 January, Evening Shift — Question 63

The correct increasing order of spin-only magnetic moment values of the complex ions $\left[\mathrm{MnBr}_{4}\right]^{2-}(\mathrm{A}),\left[\mathrm{Cu}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}(\mathrm{B}),\left[\mathrm{Ni}\left(\mathrm{CN}_{4}\right)\right]^{2-} (\mathrm{C})$ and $\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}(\mathrm{D})$ is:

Option A:
A $=$ B $<$ C $<$ D
Option B:
A $=$ B $<$ D $<$ C
Option C:
C $=$ D $<$ B $<$ A
Option D:
C $<$ B $<$ D $<$ A
Correct

Answer: D

Step-by-step solution

$\mathrm{Mn}^{2+} 3 \mathrm{~d}^{5} \mathrm{n}=5$ $\mathrm{Cu}^{2+} 3 \mathrm{~d}^{9} \mathrm{t}_{2 \mathrm{~g}}^{2,2,2} \mathrm{e}_{\mathrm{g}}^{2,1} \mathrm{n}=1$ $\mathrm{Ni}^{2+} 3 \mathrm{~d}^{8}$ square planar $\mathrm{n}=0$ $\mathrm{Ni}^{2+} 3 \mathrm{~d}^{8}$ tetrahedral $\mathrm{e}^{2,2} \mathrm{t}_{2}^{2,1,1} \mathrm{n}=2$

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Exam: JEE Main 2026
Paper: 28 January, Evening Shift
Subject: Chemistry
Chapter: Coordination Compounds
Topic: Properties and importance of Coordination Complexes

The number of isoelectronic species among Sc^3+ , Cr^2+, Mn^3+, Co^3+ and Fe^3+ is ' n '. If ' n ' moles of AgCl is formed during the…

Answer: D

Step-by-step solution

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