Use the formulae of the species involved to identify the conjugate acid-base pair in this reaction.
Define what a buffer solution is.
Write two equations to show how a mixture of $(\text{Na}^+)_2(\text{HPO}_4^{2-})$ and $\text{Na}^+(\text{H}_2\text{PO}_4^-)$ can act as a buffer solution.
Identify one inorganic ion that helps buffer blood.
Compound E is the hydroxide of a Group 2 element. Compound E is a strong alkali. $2.63\,\text{g}$ of E is dissolved in water to make $250\,\text{cm}^3$ of solution F. The $\text{pH}$ of solution F is $13.09$ at $298\,\text{K}$. Show that the hydroxide ion concentration in solution F is $0.123\,\text{mol dm}^{-3}$.
Explain why the concentration of compound E in solution F is $0.0615\,\text{mol dm}^{-3}$.
Identify compound E using the concentration given in (ii).
Compound E is much more soluble than magnesium hydroxide. A saturated solution of magnesium hydroxide in water has a concentration of $1.40 \times 10^{-4}\,\text{mol dm}^{-3}$ at $298\,\text{K}$. Calculate the solubility product, $K_{sp}$, of magnesium hydroxide. Include units.
Explain why compound E is much more soluble than magnesium hydroxide.