Find the total number of moles of donor atoms present in one mole trioxalatocobaltate(III) ion.
Find the total number of moles of donor atoms present in one mole trioxalatocobaltate(III) ion.
6
3
12
4
Solution
In $\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}$, three oxalate ligands are attached to the cobalt ion. Since oxalate is a bidentate ligand, each $\left(\mathrm{C}_2 \mathrm{O}_4\right)^{2-}$ has two donor oxygen atoms.
1 mole of $\left(\mathrm{C}_2 \mathrm{O}_4\right)^{2-} \equiv 2$ moles of donor atoms.
$\therefore 1$ mole of $\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-} \equiv 3 \times 2=6$ moles of donor atoms.