JEE Main 2025 — Coordination Compounds Question with Solution

(A) $\left[\mathrm{Ni}(\mathrm{CO}{)}_4\right],{\mathrm{Ni}}^0:[\mathrm{Ar}]3{\mathrm{d}}^{8}4{\mathrm{s}}^2$

Valence orbitals of ${\mathrm{Ni}}^0$ in pre-hybridisation state :

Tetrahedral, Diamagnetic, $\mu =0$ B.M.

(B) ${\left[\mathrm{Ni}(\mathrm{CN}{)}_4\right]}^{2-},{\mathrm{Ni}}^{+2}:[\mathrm{Ar}]3{\mathrm{d}}^{8}4{\mathrm{s}}^0$

Valence orbitals of ${\mathrm{Ni}}^{+2}$ in pre-hybridisation state :

Square planar, Diamagnetic, $\mu =0$ B.M.

(C) ${\left[{\mathrm{NiCl}}_4\right]}^{2-},{\mathrm{Ni}}^{+2}:[\mathrm{Ar}]3{\mathrm{d}}^{8}4{\mathrm{s}}^0$

Valence orbitals of ${\mathrm{Ni}}^{+2}$ in ground state :

Tetrahedral, paramagnetic, $\mu =\sqrt{8}=2.8$ B.M.

(D) ${\left[{\mathrm{MnBr}}_4\right]}^{2-},{\mathrm{Mn}}^{+2}:[\mathrm{Ar}]3{\mathrm{d}}^5$

Valence orbitals of ${\mathrm{Mn}}^{+2}$ in ground state :

Tetrahedral, paramagnetic, $\mu =\sqrt{35}=5.9$ B.M.