1
JEE Main 2025 (Online) 23rd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

$\mathrm{CrCl}_3 \cdot \mathrm{xNH}_3$ can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of $0.558^{\circ} \mathrm{C}$. Assuming $100 \%$ ionisation of this complex and coordination number of Cr is 6 , the complex will be (Given $\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ )

A
$\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2$
B
$\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}$
C
$\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$
D
$\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}_3\right]$
2
JEE Main 2025 (Online) 23rd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The d-electronic configuration of an octahedral Co (II) complex having magnetic moment of 3.95 BM is:

A
$e^4 t_2^3$
B
$\mathrm{t}_{2 \mathrm{~g}}{ }^6 \mathrm{e}_{\mathrm{g}}{ }^1$
C
$\mathrm{t}_{2 \mathrm{~g}}{ }^5 \mathrm{e}_{\mathrm{g}}{ }^2$
D
$t_{2 g^3}^3 e_g^0$
3
JEE Main 2025 (Online) 23rd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The complex that shows Facial - Meridional isomerism is :

A
$\left[\mathrm{Co}(\mathrm{en})_2 \mathrm{Cl}_2\right]^{+}$
B
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}_3\right]$
C
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right]^{+}$
D
$\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}$
4
JEE Main 2025 (Online) 22nd January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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

A
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}<\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}$
B
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+}<\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
C
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+}<\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}$
D
$\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{2+}<\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_4\right]^{2+}$
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