Chemistry Class 12 NCERT Solutions: Chapter 9 Coordination Compounds Part 6

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Q: 15. Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory:

(i)

(ii)

(iii)

(iv)

Answer:

In the above coordination complex, iron exists in the oxidation state. : Electronic configuration is

Orbitals of :

Q 15 i 1 Orbitals of Fe2+ ion

Q 15 I 1 Orbitals of Fe2+ Ion

Q 15 i 1 Orbitals of Fe2+ ion

As is a strong field ligand, it causes the pairing of the unpaired electrons.

Q 15 i 2 The Pairing of The Unpaired 3d Electrons

Q 15 I 2 the Pairing of the Unpaired 3d Electrons

Q 15 i 2 The Pairing of The Unpaired 3d Electrons

Since there are six ligands around the central metal ion, the most feasible hybridization is .

hybridized orbitals of are:

Q 15 i 3 The Hybridized Orbitals

Q 15 I 3 the Hybridized Orbitals

Q 15 i 3 The Hybridized Orbitals

electron pairs from ions occupy the six hybrid orbitals. Then,

Q 15 i 4 6 Pairs Of Electrons

Q 15 I 4 6 Pairs of Electrons

Q 15 i 4 6 Pairs Of Electrons

Hence, the geometry of the complex is octahedral and the complex is diamagnetic (as there are no unpaired electrons).

(ii)

In this complex, the oxidation state of is

Orbitals of :

Q 15 ii 1 Orbitals of Fe +3 Ion

Q 15 Ii 1 Orbitals of Fe +3 Ion

Q 15 ii 1 Orbitals of Fe +3 Ion

There are ions. Thus, it will undergo or hybridization. As is a weak field ligand, it does not cause the pairing of the electrons in the orbital. Hence, the most feasible hybridization is .

hybridized orbitals of are:

Q 15 ii 2 Hybridized Orbitals of Fe

Q 15 Ii 2 Hybridized Orbitals of Fe

Q 15 ii 2 Hybridized Orbitals of Fe

Q 15 ii 3 6 Electron Pair From F- Ions

Q 15 Ii 3 6 Electron Pair from F- Ions

Q 15 ii 3 6 Electron Pair From F- Ions

Hence, the geometry of the complex is found to be octahedral.

(iii)

Cobalt exists in the oxidation state in the given complex.

Orbitals of :

Q 15 iii 3 Orbitals Of Co^3+ Ions

Q 15 Iii Orbitals of Co^3+ Ions

Q 15 iii 3 Orbitals Of Co^3+ Ions

Oxalate is a weak field ligand. Therefore, it cannot cause the pairing of the orbital electrons. As there are ligands, hybridization has to be either hybridization.

hybridization of :

Q 15 iii 2 Hybridization of Co^3+

Q 15 Iii 2 Hybridization of Co^3+

Q 15 iii 2 Hybridization of Co^3+

The electron pairs from the oxalate ions (oxalate anion is a bidentate ligand) occupy these orbitals.

Q 15 iii 3 6 Electron Pairs From 3 Oxalate Ions

Q 15 Iii 3 6 Electron Pairs from 3 Oxalate Ions

Q 15 iii 3 6 Electron Pairs From 3 Oxalate Ions

Hence, the geometry of the complex is found to be octahedral.

(iv)

Cobalt exists in the oxidation state

Orbitals of ion:

Q 15 iv 1 Hybridized Orbitals

Q 15 Iv 1 Hybridized Orbitals

Q 15 iv 1 Hybridized Orbitals

Again, fluoride ion is a weak field ligand. It cannot cause the pairing of the electrons As a result, the ion will undergo hybridization. hybridized orbitals of ion are:

Q 15 iv 2 Hybridized Orbitals

Q 15 Iv 2 Hybridized Orbitals

Q 15 iv 2 Hybridized Orbitals

Q 15 iv 3 6 electron Pairs From 3 Oxalate Ions

Q 15 Iv 3 6 Electron Pairs from 3 Oxalate Ions

Q 15 iv 3 6 electron Pairs From 3 Oxalate Ions

Hence, the geometry of the complex is octahedral and paramagnetic.