What does the term conjugate acid-base pair mean?
State the formulae of the conjugate acid and the conjugate base of the hydrogen phosphate ion, $\text{HPO}_4^{2-}$.
At $298\,\text{K}$, propanoic acid, $\text{CH}_3\text{CH}_2\text{COOH}$, has $K_a = 1.35 \times 10^{-5}\,\text{mol dm}^{-3}$. Solution C contains $\text{CH}_3\text{CH}_2\text{COOH}$ and has pH 3.60 at $298\,\text{K}$. Calculate the concentration of $\text{CH}_3\text{CH}_2\text{COOH}$ in solution C.
Calculate the hydroxide ion concentration in solution C.
Calculate the concentration of a solution of hydrochloric acid that has the same pH as solution C.
Table 3.1 presents three possible values for the $K_a$ of dimethylpropanoic acid, $(\text{CH}_3)_3\text{CCOOH}$. Put a tick in Table 3.1 to indicate the correct value, then explain your choice.
Solution D is prepared by combining $100\,\text{cm}^3$ of $0.100\,\text{mol dm}^{-3}$ $\text{CH}_3\text{CH}_2\text{COOH}$ with $100\,\text{cm}^3$ of $0.100\,\text{mol dm}^{-3}$ $\text{NaCl}$. The pH of solution D is measured while small amounts of $\text{H}_2\text{SO}_4\text{(aq)}$ are added to it, and also while small amounts of $\text{NaOH(aq)}$ are added to it. Solution D behaves as a buffer solution only when one of these solutions is added to it. Complete the sentence and write an equation for the reaction that occurs. Solution D acts as a buffer when ................................ is added to it. Equation ................................
Complete the sentence and explain why solution D does not act as a buffer when the other solution is added. Solution D does not act as a buffer when ................................ is added to it. Explanation ................................
$\text{Manganese(II) hydroxide, Mn(OH)}_2$, is only slightly soluble in water. Its solubility is $3.28 \times 10^{-3}\,\text{g dm}^{-3}$ at $298\,\text{K}$. Calculate the concentration of a saturated solution of $\text{Mn(OH)}_2$ at $298\,\text{K}$. $[\text{Mn(OH)}_2] = \ldots\,\text{mol dm}^{-3}$.
State an expression for the $K_{sp}$ of $\text{Mn(OH)}_2$, and give the units of $K_{sp}$.
Use your answers to (d)(i) and (d)(ii) to calculate the value of the $K_{sp}$ of $\text{Mn(OH)}_2$ at $298\,\text{K}$.