State the acid and insoluble base that can be used to prepare magnesium chloride.
Describe the practical method used to obtain pure crystals of magnesium chloride from this acid and base.
Barium sulfate can be made in a precipitation reaction by mixing aqueous barium chloride with aqueous potassium sulfate. Write the ionic equation for this reaction, including state symbols.
Calculate the greatest mass of potassium sulfate, $\text{K}_2\text{SO}_4$, that could be made.\n\n$2\text{KOH} + \text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + 2\text{H}_2\text{O}$\n\nIn an experiment, $20.0\,\text{cm}^3$ of $0.650\,\text{mol dm}^{-3}$ sulfuric acid is exactly neutralised by aqueous potassium hydroxide.\n\nThe relative formula mass of $\text{K}_2\text{SO}_4$ is 174.
When crystallisation had finished, $1.72\,\text{g}$ of dry potassium sulfate was collected. Calculate the percentage yield of potassium sulfate.