The co-ordination number of $\mathrm{Fe}$ and $\mathrm{Co}$ in the complex ions, ${\left[\mathrm{Fe}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]}^{3-}$ and ${\left[\mathrm{Co}(\mathrm{SCN}{)}_4\right]}^{2-}$ are respectively :

Addition of excess of ${\mathrm{AgNO}}_3$ to an aqueous solution of $1$ mole of ${\mathrm{PdCl}}_2·4{\mathrm{NH}}_3$ gives $2$ moles of $\mathrm{AgCl}$. The conductivity of this solution corresponds to: