Write the expression for the $K_a$ of $\text{Cl}(\text{CH}_2)_3\text{CO}_2\text{H}(aq)$.
Write a mathematical expression showing the relationship between $K_a$ and $pK_a$.
Calculate $[\text{H}^+]$ for solutions $Y$ and $Z$.
Calculate the ratio $\dfrac{[\text{HCl}]\ \text{dissolved in solution } Y}{[\text{Cl}(\text{CH}_2)_3\text{CO}_2\text{H}]\ \text{dissolved in solution } Z}$.
A buffer with pH $5.00$ is prepared by adding sodium propanoate to $5.00\,\text{g}$ of propanoic acid in $100\,\text{cm}^3$ of distilled water. Calculate the mass of sodium propanoate needed to make this buffer solution. The $K_a$ of propanoic acid is $1.35 \times 10^{-5}\,\text{mol dm}^{-3}$. $[M_r:\ \text{propanoic acid},\ 74.0;\ \text{sodium propanoate},\ 96.0]$.
A small amount of dilute sulfuric acid is added to a small sample of the buffer described in part (b). The pH of the resulting mixture is close to $1$. Explain this observation.