Match List I with List II [2025]
| List-I | List-II | ||
| (Complex) | (Hybridisation & Magnetic characters) | ||
| (A) | (I) | & diamagnetic | |
| (B) | (II) | & paramagnetic | |
| (C) | (III) | & diamagnetic | |
| (D) | (IV) | & paramagnetic |
Choose the correct answer from the options given below:
(2)
(A)
Oxidation number of Mn = +2

For coordination number 4 as in given complex, possible shapes are square planar (with hybridization) or tetrahedral (with hybridization). For hybridization, electrons in 3d orbital need to pair up to make one d orbital vacant. But since bromide is a weak field ligand, it cannot cause pairing.

So this is hybridized and paramagnetic.
(B)
Oxidation number of Fe = +3

is a weak field ligand. It cannot pair up d electrons. Thus 4d orbitals are used for hybridization. Six pairs from six are accommodated in these six orbitals.

As it has unpaired electrons, it is paramagnetic.
(C)
Oxidation number of Co = +3

With , in octahedral complexes, and act as strong field ligands.

As all electrons are paired, it is diamagnetic.
(D)
Oxidation number of Ni = 0

CO is a strong field ligand. It shifts 4s electrons to 3d orbital to give configuration.

4s orbital becomes vacant. Ni then undergoes hybridization and lone pairs from CO are accommodated in orbitals.

As all electrons are paired, it is diamagnetic. As hybridization is , it is tetrahedral.