Compare and explain the relative acidities of 2-chloropropanoic acid, 3-chloropropanoic acid, and propanoic acid. Give your explanation.
The $K_a$ values for methanoic acid, $\text{HCO}_2\text{H}$, and pyruvic acid, $\text{CH}_3\text{COCO}_2\text{H}$, are supplied. An equilibrium mixture containing the two acid-base pairs is set up: $\text{HCO}_2^- + \text{CH}_3\text{COCO}_2\text{H} \rightleftharpoons \text{HCO}_2\text{H} + \text{CH}_3\text{COCO}_2^-$ Use the $K_a$ values to calculate the equilibrium constant, $K_{eq}$, for this equilibrium.
Use your value of $K_{eq}$ to predict where this equilibrium lies. Show this by placing a tick ($\checkmark$) in the correct box in the table. Explain your answer.
Ethanedioic acid, $\text{HO}_2\text{CCO}_2\text{H}$, has two dissociation constants, $K_{a1}$ and $K_{a2}$, and their $pK_a$ values are 1.23 and 4.19. Write equations to represent the two dissociation steps that correspond to these $pK_a$ values.
State the mathematical relationship connecting $pK_a$ and the acid dissociation constant $K_a$.
Three tests were performed on separate samples of the organic acids shown in the table, and the results below were recorded. $\checkmark$ = change observed, $\times$ = no reaction seen. Fill in the table with the reagent(s) and conditions, plus the observed change for each test. Assume that all of these organic acids have similar acid strength.
Ethanedioic acid, HO$_2$CCO$_2$H, has two dissociation constants, $K_{a1}$ and $K_{a2}$, and their $pK_a$ values are 1.23 and 4.19. Suggest equations to show the two dissociations that correspond to these $pK_a$ values. $pK_{a1}$ 1.23 $pK_{a2}$ 4.19
State how $pK_a$ is related to the acid dissociation constant $K_a$.
A sample of pyruvic acid, CH$_3$COCO$_2$H, is analysed by carbon-13 NMR spectroscopy. Three peaks are observed. Complete the table by: • circling the carbon atom responsible for the chemical shift • stating the hybridisation of the circled carbon atom.
An ester of pyruvic acid, F, is dissolved in CDCl$_3$ and analysed by proton NMR spectroscopy. The proton NMR spectrum of F is shown. Use the proton NMR spectrum of F to complete the table.
Deuterium oxide, D$_2$O, where D is $^{2}_{1}$H, can be used as a solvent in proton NMR spectroscopy. The proton NMR spectrum of alanine in CDCl$_3$ has 4 peaks. The proton NMR spectrum of alanine in D$_2$O$ has 2 peaks. On the diagram of alanine, circle the protons that show peaks in both NMR spectra. Explain your answer.
The ionic product, $K_w$, for D$_2$O has a value of $1.35 \times 10^{-15}\ \text{mol}^2\text{dm}^{-6}$ at 298 K. Write the expression for the $K_w$ of D$_2$O.
Calculate the pH of pure, neutral D$_2$O at 298 K. Treat $[\text{D}^+]$ as equivalent to $[\text{H}^+]$ when doing the pH calculation.