Compare and explain the relative acidities of 2-chloropropanoic acid, 3-chloropropanoic acid, and propanoic acid. Explain your answer. >........................................................... >........................................................... most acidic least acidic explanation

1. (a)Compare and explain the relative acidities of 2-chloropropanoic acid, 3-chloropropanoic acid, and propanoic acid. Explain your answer. >........................................................... >........................................................... most acidic least acidic explanation[3]
2. (b)(i)The numerical values of Ka for methanoic acid, HCO2H, and pyruvic acid, CH3COCO2H, are given. acid Ka HCO2H 1.78 x 10-4 CH3COCO2H 4.07 x 10-3 An equilibrium mixture containing the two acid-base pairs is formed. HCO2¯ + CH3COCO2H ⇌ HCO2H + CH3COCO2¯ Use the Ka values to calculate the equilibrium constant, Keq, for this equilibrium. Keq = [1]
3. (b)(ii)Use your value of Keq to predict the position of this equilibrium. Indicate this by placing a tick (✔) in the appropriate box in the table. Explain your answer. equilibrium lies equilibrium lies equilibrium lies to the left in the middle to the right[1]
4. (b)(iii)Ethanedioic acid, HO2CCO2H, has two dissociation constants, Ka1 and Ka2, whose pKa values are 1.23 and 4.19. Suggest equations to show the two dissociations that give rise to these pKa values. pKa1 1.23 pKa2 4.19[2]
5. (b)(iv)State the mathematical relationship between pKa and the acid dissociation constant Ka.[1]
6. (c)Three tests were carried out on separate samples of the organic acids shown in the table. The following results were obtained. ✓ = observed change X = no observed reaction [Table with test 1, 2, 3 rows and columns for reagent(s) and conditions, HCO2H, CH3COCO2H, HO2CCO2H, observed change. Some cells contain ✓ or X, others are blank.] Complete the table with the reagent(s) and conditions and the observed change for each test. Assume these organic acids all have a similar acid strength.[5]
7. (d)A sample of pyruvic acid, CH3COCO2H, 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. [Table with chemical shift (δ) values 27, 163, 192 and blank columns for carbon atom responsible and hybridisation.][2]
8. (e)An ester of pyruvic acid, F, is dissolved in CDCl3 and analysed by proton NMR spectroscopy. [Figure showing the structure of compound F, an ester of pyruvic acid: CH3-C(=O)-CO-OCH2CH3] The proton NMR spectrum of F is shown. [Figure showing the proton NMR spectrum of F with peaks at approximately 1.3, 2.2, 4.0 ppm] Use the proton NMR spectrum of F to complete the table. [Table with chemical shift (δ) values 1.3, 2.2, 4.0 and blank columns for group responsible, splitting pattern, and number of 1H atoms.][3]
9. (f)Deuterium oxide, D2O, where D is 2H, can be used as a solvent in proton NMR spectroscopy. The proton NMR spectrum of alanine in CDCl3 has 4 peaks. The proton NMR spectrum of alanine in D2O has 2 peaks. alanine [Figure showing the structure of alanine: NH2-CH(CH3)-COOH] On the diagram of alanine, circle the protons that show peaks in both NMR spectra. Explain your answer.[2]
10. (g)(i)The ionic product, Kw, for D2O has a value of 1.35 × 10-15 mol² dm–6 at 298 K. Write the expression for the Kw of D2O. Kw =[1]
11. (g)(ii)Calculate the pH of pure, neutral D2O at 298 K. Assume [D+] is equivalent to [H+] for pH calculations. pH =[2]

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