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Chemistry · Coordination Compounds

JEE Main 2025 — 7 April, Evening Shift — Question 20

The number of paramagnetic metal complex species among

[Co(NH3)6]3+,[Co(C2O4)3]3−\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}, \quad\left[\mathrm{Co}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3-}, [MnCl6]3−,[Mn(CN)6]3−,[CoF6)3−,[Fe(CN)6]3−\left[\mathrm{MnCl}_{6}\right]^{3-},\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{3-},\left[\mathrm{CoF}_{6}\right)^{3-},\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-} and [FeF6]3−\left[\mathrm{FeF}_{6}\right]^{3-} with same number of unpaired electrons is

Answer: 2

Numerical answer — enter this value.

Step-by-step solution

[Co(NH3)6]3+⇒Co3+,d6,t2 g6eg0⇒\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+} \Rightarrow \mathrm{Co}^{3+}, \mathrm{d}^{6}, \mathrm{t}_{2 \mathrm{~g}}^{6} \mathrm{e}_{\mathrm{g}}^{0} \Rightarrow diamagnetic

[Co(C2O4)3]3−⇒Co3+,d6,t2 g6eg0⇒\left[\mathrm{Co}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3-} \Rightarrow \mathrm{Co}^{3+}, \mathrm{d}^{6}, \mathrm{t}_{2 \mathrm{~g}}^{6} \mathrm{e}_{\mathrm{g}}^{0} \Rightarrow diamagnetic

[MnCl6]3−⇒Mn3+,d4,t2 g3eg1⇒4\left[\mathrm{MnCl}_{6}\right]^{3-} \Rightarrow \mathrm{Mn}^{3+}, \mathrm{d}^{4}, \mathrm{t}_{2 \mathrm{~g}}^{3} \mathrm{e}_{\mathrm{g}}^{1} \Rightarrow 4 unpaired electron, paramagnetic

[CoF6]3−⇒Co3+,d6,t2 g4eg2⇒4\left[\mathrm{CoF}_{6}\right]^{3-} \Rightarrow \mathrm{Co}^{3+}, \mathrm{d}^{6}, \mathrm{t}_{2 \mathrm{~g}}^{4} \mathrm{e}_{\mathrm{g}}^{2} \Rightarrow 4 unpaired electron, paramagnetic

[Fe(CN)6]3−⇒Fe3+,d5,t2 g5eg0⇒1\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-} \Rightarrow \mathrm{Fe}^{3+}, \quad \mathrm{d}^{5}, \quad \mathrm{t}_{2 \mathrm{~g}}^{5} \mathrm{e}_{\mathrm{g}}^{0} \Rightarrow 1 unpaired electron, paramagnetic

[FeF6]3−⇒Fe3+,d5,t2 g3eg2⇒5\left[\mathrm{FeF}_{6}\right]^{3-} \Rightarrow \mathrm{Fe}^{3+}, \mathrm{d}^{5}, \mathrm{t}_{2 \mathrm{~g}}^{3} \mathrm{e}_{\mathrm{g}}^{2} \Rightarrow 5 unpaired electron

Answer key and solution verified before publishing.

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Exam
JEE Main 2025
Paper
7 April, Evening Shift
Subject
Chemistry
Chapter
Coordination Compounds
Topic
Properties and importance of Coordination Complexes

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