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The correct order of the following complexes in terms of their crystal field stabilization energies is :

JEE Main 2025 — Chemistry Inorganic Chemistry

2025mcqhard

The correct order of the following complexes in terms of their crystal field stabilization energies is :

Official previous-year question

Held on 22 Jan 2025 · Verified 6 Jul 2026.

Options

  1. A

    [Co(NH3)4]2+<[Co(NH3)6]2+<[Co(en)3]3+<[Co(NH3)6]3+\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+} \lt \left[\mathrm{Co}(\mathrm{en})_3\right]^{3+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}[Co(NH3​)4​]2+<[Co(NH3​)6​]2+<[Co(en)3​]3+<[Co(NH3​)6​]3+

  2. B

    [Co(NH3)6]2+<[Co(NH3)6]3+<[Co(NH3)4]2+<[Co(en)3]3+\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+} \lt \left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}[Co(NH3​)6​]2+<[Co(NH3​)6​]3+<[Co(NH3​)4​]2+<[Co(en)3​]3+

  3. C

    [Co(en)3]3+<[Co(NH3)6]3+<[Co(NH3)6]2+<[Co(NH3)4]2+\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+}[Co(en)3​]3+<[Co(NH3​)6​]3+<[Co(NH3​)6​]2+<[Co(NH3​)4​]2+

  4. D

    [Co(NH3)4]2+<[Co(NH3)6]2+<[Co(NH3)6]3+<[Co(en)3]3+\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+} \lt \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+} \lt \left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}[Co(NH3​)4​]2+<[Co(NH3​)6​]2+<[Co(NH3​)6​]3+<[Co(en)3​]3+

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