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Chemistry · Coordination Compounds

JEE Main 2025 — 3 April, Evening Shift — Question 2

Identify the diamagnetic octahedral complex ions from below :

A. [Mn(CN)6]3−\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{3-}

B. [Co(NH3)6]3+\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}

C. [Fe(CN)6]4−\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}

D. [Co(H2O)3 F3]\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{3} \mathrm{~F}_{3}\right]

Choose the correct answer from the options given below.

  1. Option A:

    B and D only

  2. Option B:

    B and C only

    Correct
  3. Option C:

    A and C only

  4. Option D:

    A and D only

Answer: B

Step-by-step solution

[Mn(CN)E3−:Mn3+:[Ar]4 s03 d4:t24e90\left[\mathrm{Mn}(\mathrm{CN}) \mathrm{E}^{3-}: \mathrm{Mn}^{3+}:[\mathrm{Ar}] 4 \mathrm{~s}^{0} 3 \mathrm{~d}^{4}: \mathrm{t}_{2}{ }^{4} \mathrm{e}_{9}{ }^{0}\right. Octahedral, paramagnetic

[Co(NH3)6]3+:Co3+:[Ar]4 s03 d6:t2 g6eg0\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}: \mathrm{Co}^{3+}:[\mathrm{Ar}] 4 \mathrm{~s}^{0} 3 \mathrm{~d}^{6}: \mathrm{t}_{2 \mathrm{~g}}{ }^{6} \mathrm{e}_{\mathrm{g}}{ }^{0} Octahedral, diamagnetic

[Fe(CN)6]4−:Fe2+:[Ar]4 s03 d6:tg6eg0\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}: \mathrm{Fe}^{2+}:[\mathrm{Ar}] 4 \mathrm{~s}^{0} 3 \mathrm{~d}^{6}: \mathrm{t}_{\mathrm{g}}{ }^{6} \mathrm{eg}^{0} Octahedral, diamagnetic

[Co(H2O)3 F3]:Co3+:[Ar]4 s03dd6:t2 g4eg2\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{3} \mathrm{~F}_{3}\right]: \mathrm{Co}^{3+}:[\mathrm{Ar}] 4 \mathrm{~s}^{0} 3 \mathrm{dd}^{6}: \mathrm{t}_{2 \mathrm{~g}}{ }^{4} \mathrm{e}_{\mathrm{g}}{ }^{2} Octahedral, paramagnetic

Answer key and solution verified before publishing.

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