Find the percentage by mass of potassium in potassium sulfate, K$_2$SO$_4$.
Describe a test for sulfate ions. State the test and the result.
Explain why nitrates from solid fertilisers applied to soil can leach through the soil so readily.
Nitrates cause eutrophication. What does the term eutrophication mean?
Dilute phosphoric acid, H$_3$PO$_4$(aq), reacts with aqueous potassium hydroxide to form potassium phosphate: $\text{H}_3\text{PO}_4(aq) + 3\text{KOH}(aq) \rightarrow \text{K}_3\text{PO}_4(aq) + 3\text{H}_2\text{O}(l)$. A student titrates 25.0 cm$^3$ of H$_3\text{PO}_4$(aq) using 0.200 mol/dm$^3$ KOH(aq). 12.5 cm$^3$ of KOH(aq) is needed to react exactly with the H$_3\text{PO}_4$(aq). Calculate the concentration of the H$_3\text{PO}_4$(aq).