plumiCarboxylic acids and esters: OCR A‑Level Chemistry A questions
Every OCR A-Level Chemistry A exam question on 6.1.3 Carboxylic acids and esters, 2016–2025, with its mark scheme and examiner’s report.
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Q18(c)
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Q21(e)
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Q22(b)(i)
The whole paper ↗![June 2025 Paper 2, question 22(b)(i): Draw the structures of the organic products you would expect from the decomposition of the two other β-keto acids below. O O OH O O OH [2]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43202-jun25-22-bi-qp.webp?v=3)
Q17(d)
The whole paper ↗![June 2024 Paper 2, question 17(d): Esterification reaction of (CH3)3COH Reagent(s) and/or catalyst organic product [2]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43202-jun24-17-d-qp.webp?v=3)
Q20(a)
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Q20(b)(i)
The whole paper ↗![June 2024 Paper 2, question 20(b)(i): What is the systematic name for this ester? [1]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43202-jun24-20-bi-qp.webp?v=3)
Q20(b)(ii)
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Q20(d)
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Q23(b)(i)
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![June 2023 Paper 2, question 12: Which compound reacts with ethanoyl chloride? O A O B O Cl C O D NH2 O Your answer [1]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43202-jun23-12-qp.webp?v=3)
Q20(a)
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Q5(b)(ii)
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Q19(a)
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Q19(b)
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Q20(f)
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Q6(b)(ii)
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All 46 questions on Carboxylic acids and esters, as a list
- June 2025, Paper 2, Q9 (1 mark): Which reagents could a student use to prepare the ester shown? O CH3CH2 C O O A OH CH3CH2 C + HO CH3CH2 OH + HOOC B C CH3CH2CH2 OH + HOOC O D CH3CH2 C Cl + HO Y
- June 2025, Paper 2, Q18(c) (2 marks): 3-Hydroxybutanoic acid reacts with ethanoic anhydride, (CH3CO)2O. Complete the equation for this reaction. Show the structures of the organic compounds. CH3 O O
- June 2025, Paper 2, Q21(e) (7 marks): Complete the flowchart for the reactions of pyruvic acid. excess NH3 Acyl chloride Compound P reagent(s) O NaOH(aq) O OH Pyruvic acid CH3OH / H2SO4 reagent(s) O
- June 2025, Paper 2, Q22(b)(i) (2 marks): Draw the structures of the organic products you would expect from the decomposition of the two other β-keto acids below. O O OH O O OH [2]
- June 2024, Paper 2, Q17(d) (2 marks): Esterification reaction of (CH3)3COH Reagent(s) and/or catalyst organic product [2]
- June 2024, Paper 2, Q20(a) (2 marks): Short-chain carboxylic acids, such as methanoic acid, HCOOH, are soluble in water. Explain, with a labelled diagram, how HCOOH interacts with water when it diss
- June 2024, Paper 2, Q20(b)(i) (1 mark): What is the systematic name for this ester? [1]
- June 2024, Paper 2, Q20(b)(ii) (4 marks): Ester F can be prepared from a carboxylic acid in two steps. Step 1 The carboxylic acid is converted into an acyl chloride. Step 2 The acyl chloride is converte
- June 2024, Paper 2, Q20(d) (4 marks): The compound below contains an ester and an amide group. O N O H O Draw the structures of the organic products formed by the complete alkaline hydrolysis of thi
- June 2024, Paper 2, Q23(b)(i) (3 marks): In Step 2, Na2CO3(aq) removes the sulfuric acid catalyst and any unreacted compound G from the mixture. Write equations for this removal. Removal of sulfuric ac
- June 2023, Paper 2, Q12 (1 mark): Which compound reacts with ethanoyl chloride? O A O B O Cl C O D NH2 O Your answer [1]
- June 2023, Paper 2, Q14 (1 mark): Which compound(s) is/are hydrolysed by HCl (aq) to produce butanoic acid? 1 CH3CH2CH2COOCH3 2 CH3CH2CH2CH2CN 3 CH3CH2CH2CH2Cl A 1, 2 and 3 B Only 1 and 2 C Only
- June 2023, Paper 2, Q20(a) (4 marks): Salicylic acid, shown below, is used in the manufacture of some important medicines. COOH OH Salicylic acid Complete the flowchart for reactions of salicylic ac
- June 2023, Paper 3, Q5(b)(ii) (3 marks): In this reaction, 1 mol of aspirin reacts with 3 mol of hot NaOH(aq). Complete the equation for the reaction of aspirin with an excess of hot NaOH(aq). Show str
- June 2022, Paper 2, Q10 (1 mark): Butyl propanoate is hydrolysed by aqueous sodium hydroxide. Which compound is one of the products of this hydrolysis? A C3H7ONa B C3H5O2Na C C4H9ONa D C4H7O2Na
- June 2022, Paper 2, Q19(a) (4 marks): Carboxylic acids react with alkalis, metals and carbonates to form salts. Write full equations for the following three reactions. Show structures for organic co
- June 2022, Paper 2, Q19(b) (4 marks): The structure of 2-hydroxybutanoic acid is shown below. H CH3CH2 C COOH OH 2-hydroxybutanoic acid Fill in the flowchart for reactions involving 2-hydroxybutanoi
- June 2022, Paper 2, Q20(f) (2 marks): Acid anhydrides react in a similar way to acyl chlorides with phenols. Benzoic anhydride is the acid anhydride of benzoic acid, C6H5COOH. Benzoic anhydride reac
- June 2022, Paper 3, Q6(b)(ii) (2 marks): A ‘vitamin C ester’ tablet contains an ester with the molecular formula C22H38O7. This ester can be prepared by reacting vitamin C with a long chain carboxylic
- November 2021, Paper 2, Q6 (1 mark): CH3CH2COOCH3 is heated with aqueous sodium hydroxide to produce two organic products. What are the two organic products? A CH3CH2COOH and CH3OH B CH3CH2COONa an
- November 2021, Paper 2, Q15 (1 mark): Compounds 1, 2 and 3 are heated with NaOH(aq). Which compound(s) react(s)? OH 1 COOH 2 CH2Br 3 A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer [
- November 2021, Paper 2, Q18(d)(ii) (1 mark): Suggest why tablets based on a salt of ibuprofen should act faster in the body than ibuprofen. [1]
- November 2021, Paper 2, Q20(a)(iii) (3 marks): Two molecules of salicylic acid can react together in the presence of an acid catalyst to form compound B. Compound B has three rings and a molecular formula of
- November 2021, Paper 3, Q1(e) (4 marks): The structure of lactic acid is shown below. OH OH O lactic acid Complete and balance the equations for two reactions of lactic acid. Reaction with sodium carbo
- November 2020, Paper 2, Q3 (1 mark): Which of these reagent(s) will not react with HOCH2CH2CH2COOH? A NaCN in ethanol B C2H5OH in the presence of an acid catalyst C (CH3CO)2O D concentrated H2SO4 Y
- November 2020, Paper 2, Q7 (1 mark): Which one of the following reacts with ethanoic acid and with phenol? A Aqueous potassium hydroxide B Bromine C Calcium carbonate D Methanol and an acid catalys
- November 2020, Paper 2, Q9 (1 mark): What is the structural formula of ethyl 3-methylbutanoate? A CH3CH2COOCH2CH2CH(CH3)2 B CH3CH2COOCH(CH3)CH2CH3 C CH3CH2CH(CH3)COOCH2CH3 D (CH3)2CHCH2COOCH2CH3 Yo
- November 2020, Paper 2, Q14 (1 mark): Which of the following reactions produce propan-1-ol? 1 The alkaline hydrolysis of 1-chloropropane. 2 The acid hydrolysis of propyl methanoate. 3 The acid hydro
- November 2020, Paper 2, Q18(a)(ii) (2 marks): HOOC(CH2)2COOH is soluble in water. Explain, using a labelled diagram, why HOOC(CH2)2COOH is soluble in water. [2]
- November 2020, Paper 2, Q18(b)(iii) (3 marks): A large yield of polymer E can be obtained by reacting a diacyl dichloride with HO(CH2)4OH. The diacyl dichloride is prepared from HOOC(CH2)2COOH. Complete the
- November 2020, Paper 2, Q21(b)(ii) (4 marks): A sample of aspartame is hydrolysed with aqueous acid. Draw the structures of the three organic products of the complete acid hydrolysis of aspartame. [4]
- June 2019, Paper 2, Q18(a)(i) (1 mark): What is the systematic name of ester A? [1]
- June 2019, Paper 2, Q18(a)(ii) (5 marks): In the boxes, draw the organic products for the reactions of the functional groups in ester A shown below. Each reaction forms two organic products. + H+(aq) O
- June 2019, Paper 2, Q18(a)(iii) (1 mark): Name the type of reactions of ester A shown in (ii). [1]
- June 2019, Paper 2, Q18(c) (1 mark): Compound B is a structural isomer of ester A. • Compound B reacts with aqueous sodium carbonate. • The 13C NMR spectrum of B has 4 peaks. Draw a possible struct
- June 2019, Paper 3, Q2(b) (1 mark): In Step 2, explain why the mixture must be acidified so that crystals of benzoic acid appear. [1]
- June 2018, Paper 2, Q16(c) (3 marks): The flowchart below shows some reactions of compound C. In the boxes, draw the organic products of these reactions. excess CH3OH/H2SO4 Steam COOH HOOC H3PO4 com
- June 2018, Paper 2, Q21(a) (3 marks): The flowchart below shows some reactions of compound H. In the boxes, draw the organic products of these reactions. Na2CO3(aq) NaOH(aq) O C OH HO compound H Br2
- June 2018, Paper 2, Q21(b) (4 marks): Compound H is used in the synthesis of polymer I, as shown in the flowchart below. Complete the flowchart by drawing the structure of the acyl chloride and two
- June 2018, Paper 3, Q5(b)(ii) (1 mark): Write the equation for the equilibrium reaction that takes place. [1]
- June 2018, Paper 3, Q5(b)(iii) (1 mark): Draw the skeletal formula of the ester present in the equilibrium mixture. [1]
- June 2017, Paper 2, Q10 (1 mark): Equal amounts of the four compounds are added to the same volume of water. Which compound would produce the most acidic solution? A CH3CONH2 B CH3COOH C CH3COOC
- June 2017, Paper 2, Q13 (1 mark): Which reagents could be used to prepare CH3CH2CONHCH3? A CH3CH2COCl + CH3NH2 B CH3CH2CONH2 + CH3Br C CH3CH2COONa + CH3NH2 D CH3CH2COCH3 + NH3 Your answer [1]
- June 2017, Paper 3, Q4(b)(i) (3 marks): Magnesium ribbon is added to a solution of compound A. Gas bubbles are seen and the magnesium slowly dissolves. Equation Type of reaction [3]
- June 2017, Paper 3, Q4(b)(ii) (3 marks): Compound A is heated with a few drops of concentrated sulfuric acid as a catalyst. A cyclic ‘dimer’ of compound A forms. Equation Type of reaction [3]
- June 2017, Paper 3, Q5(a)(ii) (2 marks): Thiols react with carboxylic acids to form thioesters. Write an equation for the reaction of butane-1-thiol with ethanoic acid. Use structures for all organic c
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