Cobalt chloride when dissolved in water forms pink colored complex $\underline{\text{X}}$ which has octahedral geometry.
This solution on treating with conc $\text{HCl}$ forms deep blue complex, $\underline{\text{Y}}$ which has a $\underline{\text{Z}}$ geometry. $\text{X}$, $\text{Y}$ and $\text{Z}$, respectively are:
