Answer:
Phosphate ion only
Explanation:
Here, we want to get the polyatomic ions with a charge of -3
What we have to do here is to write the polyatomic ions and their formula
We have this as follows:
[tex]\begin{gathered} \text{Phosphate ion - PO}^{3-}_4 \\ \text{Acetate ion - }C_2H_3O^-_2 \\ Sulfate-SO^{2-}_{4^{}} \\ Hydro\times ide-OH^- \\ \\ \text{Dichromate - Cr}_2O^{2-}_7 \\ \text{Hydrogen phosphate - HPO}^{2-}_4 \end{gathered}[/tex]From the above, the polyatomic ions with a charge of -3 is the Phosphate ion only