Exam

JEE Main

Year

2025

Date

4 April

Shift

Morning Shift

Subject

Chemistry

Chapter

Coordination Compounds

JEE Main 2025 · 4 April · Morning Shift · Chemistry · Coordination Compounds

Which one of the following complexes will have Δ_0=0 and μ=5.96...

Which one of the following complexes will have $\Delta_0=0$ and $\mu=5.96$ B.M.?

Step-by-step solution

(1) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+} \quad \mathrm{Co}^{3+} \Rightarrow 3 \mathrm{~d}^6 4 \mathrm{~s}^0$

$=[-0.4 \times 6+0.6 \times(0)] \Delta_0=-2.4 \Delta_0$
(2)
$$\begin{aligned}<br />& {\left[\mathrm{Mn}(\mathrm{SCN})_6\right]^4} \\<br>& \mathrm{Mn}^{2+} \Rightarrow 3 \mathrm{~d}^5 4 \mathrm{~s}^0<br />\end{aligned}$$
$$\begin{aligned}<br />& \mu=\sqrt{35} \text{ B.M. }=5.96 \text{ B.M. } \\<br>& \mathrm{CFSE}=(-0.4 \times 3+0.6 \times 2) \Delta_0<br />\end{aligned}$$
So $\Delta_0=0$
(3)
$$\begin{aligned}<br />& {\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{-4} \quad \mathrm{Fe}^{2+} \Rightarrow 3 \mathrm{~d}^6 4 \mathrm{~s}^0}<br />\end{aligned}$$
$\mathrm{CFSE}=-2.4 \Delta_0$
(4) \left[\mathrm{FeF}_6\right]^{4-}$<br />$\mathrm{Fe}^{2+} \Rightarrow 3 \mathrm{~d}^6 4 \mathrm{~s}^0$<img src="https://cdn-question-pool.Quantrex.app/pyq/jee_main/zqvcznomxHPLkpqdaC4cOWvkldF0f22bBKDvUFo9-cY.original.fullsize.png"/><br />$$\begin{aligned}<br />& \mu=\sqrt{24} \text{ B.M. }=4.89 \text{ B.M. } \\<br>& \text{ CFSE }=(-0.4 \times 4+0.6 \times 2) \Delta_0=-1.2 \Delta_0<br />\end{aligned}$$