Chemistry · Coordination Compounds

JEE Main 2025 — 22 January, Evening Shift — Question 33

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

Option A:
$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4}\right]^{++}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{++}<\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$
Option B:
$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4}\right]^{++}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{++}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}<\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}$
Correct
Option C:
$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}<\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}$
Option D:
$\left.\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)\right]_{6}\right]^{2+}<\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)\right]^{2+}$

Answer: B

Order of CFSE

$SFL$ : $\mathrm{NH}_{3}<$ en

Answer key and solution verified before publishing.

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