Chapter 19, Problem 19.51QE

(a)

Interpretation Introduction

Interpretation:

The high-spin and low-spin complexes have to be identified and the number of unpaired electrons present in each complex has to be given from given set of complexes.

${{\text{[Cr(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}{\text{and [Mn(CN)}}_{\text{6}}{\text{]}}^{\text{3-}}$

Explanation of Solution

For ${{\text{[Cr(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}$ complex:

Ground state electronic configuration of $\text{Cr}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^{\text{1}}{\text{ 3d}}^{\text{5}}$

Ground state electronic configuration of ${\text{Cr}}^{\text{2+}}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^0{\text{ 3d}}^4$

Water is a weak ligand so it is forms a high-spin complex with $\text{Cr}$ and 4 unpaired electrons present in the given complex.

For ${{\text{[Mn(CN)}}_{\text{6}}\text{]}}^{\text{3-}}$ complex:

Ground state electronic configuration of $\text{Mn}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^2{\text{ 3d}}^{\text{5}}$

Ground state electronic configuration of ${\text{Mn}}^{\text{3+}}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^0{\text{ 3d}}^4$

$\text{CN}$ is a strong ligand so it is forms a low-spin complex with $\text{Mn}$ and 0 unpaired electrons present in the given complex.

(b)

Interpretation Introduction

Interpretation:

The high-spin and low-spin complexes have to be identified and the number of unpaired electrons present in each complex has to be given from given set of complexes.

${{\text{[Fe(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}{\text{ and [Ru(H}}_{\text{2}}{\text{O)}}_{\text{6}}{\text{]}}^{\text{2+}}$

Explanation of Solution

For ${{\text{[Fe(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}$ complex:

Ground state electronic configuration of $\text{Fe}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^2{\text{ 3d}}^6$

Ground state electronic configuration of ${\text{Fe}}^{\text{2+}}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^0{\text{ 3d}}^6$

Water is a weak ligand so it is forms a high-spin complex with $\text{Fe}$ and 4 unpaired electrons present in the given complex.

For ${{\text{[Ru(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}$ complex:

Ground state electronic configuration of $\text{Ru}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^{\text{2}}{\text{ 3d}}^{\text{10}}{\text{ 4p}}^{\text{6}}{\text{ 5s}}^{\text{1}}{\text{ 4d}}^{\text{8}}$

Ground state electronic configuration of ${\text{Ru}}^{\text{2+}}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^{\text{2}}{\text{ 3d}}^{\text{10}}{\text{ 4p}}^{\text{6}}{\text{ 5s}}^0{\text{ 4d}}^{\text{8}}$

$\text{Ru}$ has grater paring energy so it forms low-spin complex any ligands so there is no unpaired electrons present in the given complex.

(c)

Interpretation Introduction

Interpretation:

The high-spin and low-spin complexes have to be identified and the number of unpaired electrons present in each complex has to be given from given set of complexes.

${{\text{[Co(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}{\text{ and [Co(CN)}}_{\text{5}}{\text{(H}}_{\text{2}}{\text{O)]}}^{\text{3-}}$

Explanation of Solution

For ${{\text{[Co(H}}_{\text{2}}{\text{O)}}_{\text{6}}\text{]}}^{\text{2+}}$ complex:

Ground state electronic configuration of $\text{Co}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^{\text{2}}{\text{ 3d}}^{\text{7}}$

Ground state electronic configuration of ${\text{Co}}^{\text{2+}}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^0{\text{ 3d}}^{\text{7}}$

Water is a weak ligand so it is forms a high-spin complex with $\text{Co}$ and 3 unpaired electrons present in the given complex.

For ${\text{ [Co(CN)}}_{\text{5}}{\text{(H}}_{\text{2}}{\text{O)]}}^{\text{3-}}$ complex:

Ground state electronic configuration of $\text{Co}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^{\text{2}}{\text{ 3d}}^{\text{7}}$

Ground state electronic configuration of ${\text{Co}}^{\text{2+}}$ is,

  ${\text{1s}}^{\text{2}}{\text{ 2s}}^{\text{2}}{\text{ 2p}}^{\text{6}}{\text{ 3s}}^{\text{2}}{\text{ 3p}}^{\text{6}}{\text{ 4s}}^0{\text{ 3d}}^{\text{7}}$

$\text{CN}$ is a strong ligand so it is forms a low-spin complex with $\text{Co}$ and 1 unpaired electron present in the given complex.