Chapter 21, Problem 13Q

Interpretation Introduction

Interpretation: An explanation for the change in the color of $\text{Co}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{6}}{}^{\text{2+}}$ complex ion solution on addition of concentrated hydrochloric acid is to be stated.

Concept introduction: There is degeneracy in the d orbitals of a transition metal atom or ion. It means they have same energy levels. But when they interact with ligands, the d orbitals become non degenerate, i.e. they do not have same energy. Color of the complex ions depends upon how the 3d electrons occupy the split energy levels.

To determine: An explanation for the change in the color of $\text{Co}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{6}}{}^{\text{2+}}$ complex ion solution on addition of concentrated hydrochloric acid.