A LevelChemistryCIEExam Questions3. Organic Chemistry3.6 Carboxylic Acids & Derivatives

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Carboxylic Acids & Derivatives (CIE A Level Chemistry)

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3.6 Carboxylic Acids & Derivatives

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3.6 Carboxylic Acids & Derivatives

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11 mark

The natural bacterial fermentation of milk produces a compound called propanoic acid.  Propanoic acid is partly responsible for the flavour of Swiss cheese.

3-6-cie-ial-chemistry-diagram-q1easy

Which starting materials could be used to produce propanoic acid?

 

1

CH3CH2CN 

 

2

CH3CH2CHO

 

3

CH3CH2CH2OH

  • 1, 2 and 3

  • 1 and 2

  • 2 and 3

  • 1 only

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21 mark

Synthesis of the pharmaceutical drug aspirin requires ethanoic acid, CH3CO2H. 

Which processes can be used to make ethanoic acid?

 

1

Oxidation of ethanol 

 

2

Oxidation of ethanal

 

3

Hydrolysis of ethanenitrile

  • 1, 2 and 3

  • 1 and 2

  • 2 and 3

  • 1 only

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31 mark

‘Trans fats’ can be found in some vegetable oils and are known to lead to increased blood cholesterol levels. 

In the diagrams below, R1 and R2 are different hydrocarbon chains. 

Which diagram shows an optically active ‘trans fat’?

  • 3-6-e-3a

  • 3-6-e-3b

  • 3-6-e-3c

  • 3-6-e-3d

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41 mark

Methanoic acid is one of the two reactants used to produce an ester with the molecular formula C5H10O2. 

How many isomeric esters, including structural isomers and stereoisomers, could be made with this molecular formula?

  • 3

  • 4

  • 5

  • 6

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51 mark

The structure of ester E is shown in the diagram below. 

3-6-e-5

E is hydrolysed in the presence of hydrochloric acid. 

Which are the products of this hydrolysis?

  • CH3CO2H and (CH3)2CHCH2CH2CHO

  • CH3CO2H and (CH3)2CHCH2CH2OH

  • CH3COCl and (CH3)2CHCH2CH2OH

  • CH3CHO and (CH3)2CHCH2CH2OH

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61 mark

The ester in the diagram below has an odour of banana.

3-6-e-6

Which pair of reactants can be used to produce this ester under suitable conditions?

  • 3-6-e-6a

  • 3-6-e-6b

  • 3-6-e-6c

  • 3-6-e-6d

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71 mark

Which reaction does not produce propanoic acid?

  • Heating propanenitrile under reflux with dilute sodium hydroxide.

  • Heating propanenitrile under reflux with dilute sulfuric acid.

  • Heating propanal under reflux with acidified sodium dichromate (VI).

  • Heating propanol under reflux with acidified sodium dichromate (VI).

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81 mark

Propionitrile, CH3CH2Cidentical toN, is used to produce propanoic acid.

What are the conditions for this reaction?

  • NaOH

  • H+ / Na2Cr2O7

  • NaBH4

  • H+ / H2O

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91 mark

Sodium lactate, CH3CH(OH)CO2Na, can be produced from lactic acid, CH3CH(OH)CO2H.

Which reagents, when used in excess, can be used in this reaction?

 

1

Na

 

2

NaOH 

 

3

NaHCO3

  • 1, 2 and 3

  • 1 and 2

  • 2 and 3

  • 1 only

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101 mark

The molecule CH3CH2CH2CO2CH2CH3 is used as a pineapple flavouring in sweets.

Which statements about this molecule are correct?

 

1

When this compound is heated with aqueous sodium hydroxide, the products are butan-1-ol and sodium ethanoate.

 

2

The name of this compound is ethyl butanoate.

 

3

This compound is a structural isomer of hexanoic acid.

  • 1, 2 and 3

  • 1 and 2

  • 2 and 3

  • 1 only

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11 mark

Compound P is the only organic material required to produce the ester CH3CH2CO2CH2CH2CH3 through a sequence of reactions.

What might be the identity of compound P?

 

1

CH3COCH3 

 

2

CH3CH2CHO

 

3

CH3CH2CH2OH

  • 1, 2 and 3

  • 1 and 2

  • 2 and 3

  • 1 only

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21 mark

Sour milk contains a compound called lactic acid (2-hydroxypropanoic acid) which has the molecular formula CH3CH(OH)CO2H.

Which of the following reactions could lactic acid undergo?

  • CH3CH(OH)CO2H  +  Cl2            rightwards arrow     CH3CH(Cl)CO2H + OCl

  • CH3CH(OH)CO2H  +  HCO2H     rightwards arrow     CH3CH(O2CH)CO2H  + H2O

  • CH3CH(OH)CO2H  +  CH3OH     rightwards arrow     CH3CH(OCH3)CO2H  + H2O

  • CH3CH(OH)CO2H  +  NaHCO3   rightwards arrow     CH3CH(ONa)CO2H + H2O + CO2

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31 mark

The organic compound, C, reacts with sodium metal to produce a salt with the empirical formula NaC2H3O2.

What could be the identity of C?

 

1

Ethanoic acid 

 

2

Butanedioic acid

 

3

2-methylpropanedioic acid

  • 1, 2 and 3

  • 1 and 2

  • 2 and 3

  • 1 only

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41 mark

Cetyl palmitate is a waxy solid and has the molecular formula C15H31CO2C16H33.

Which products are formed when cetyl palmitate is heated under reflux with an excess of aqueous sodium hydroxide?

  • C15H31CO2Na and C16H33OH

  • C15H31CO2Na and C16H33ONa

  • C15H31OH and C16H33CO2Na

  • C15H31ONa and C16H33CO2Na

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51 mark

The diagram shows the structure of ethanedioic acid.

3-6-m-5

Ethanedioic acid reacts with ethanol in the presence of a few drops of concentrated sulfuric acid to form a diester. The molecular formula of the diester is C6H10O4.

What is the structural formula of the diester?

  • CH3CH2CO2CO2CH2CH3

  • CH3CH2OCOCO2CH2CH3

  • CH3CH2O2CO2CCH2CH3

  • CH3CO2CH2CH2OCOCH3

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61 mark

Apples contain a compound called malic acid.

3-6-m-6

Which substance will react with only one hydroxyl groups in malic acid under suitable conditions?

  • Na (s)

  • PCl5

  • NaOH (aq)

  • Cr2O72- / H+ (aq)

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71 mark

Lactic acid is a naturally occurring molecule. 

3-6-m-7

What is a property of lactic acid?

  • It rapidly decolourises aqueous bromine.

  • Two molecules can react together in strong acid.

  • It reduces Fehling’s reagent.

  • It is insoluble in water.

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81 mark

The ester in the diagram below is the active ingredient in sun protection creams.

3-6-cie-ial-chemistry-diagram-q8amedium

The ester is hydrolysed by aqueous sodium hydroxide. Which substances are present in the products?

3-6-cie-ial-chemistry-diagram-q8bmedium

  • 1 only

  • 1 and 2

  • 2 and 3

  • 1, 2 and 3

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91 mark

Compound Q has the formula CH3CH2CO2CH3.

What is the name of compound Q and how does its boiling point compare with that of butanoic acid?

 

Name of Q

Boiling point compared to butanoic acid

A

B

C

D

Methyl propanoate

Propyl methanoate

Methyl propanoate

Propyl methanoate

Lower 

Lower

Higher

Higher

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    101 mark

    How many ester compounds have the molecular formula C4H8O2?

    • 2

    • 3

    • 4

    • 5

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    11 mark

    In the presence of an H+ catalyst, compound X reacts with ethanoic acid to produce the compound below.

    3-6-h-1

    What is the molecular formula of compound X?

    • C4H8O

    • C4H8O2

    • C2H6O2

    • C2H6O3

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    21 mark

    Sirolimus is a drug used to treat patients after kidney transplants.

    3-6-cie-ial-chemistry-diagram-q2hard

    Sirolimus produces an equimolar mixture of two organic products, on reaction with hot aqueous sodium hydroxide.

    What is the structural formula of the product with the lower relative molecular mass?

    • 3-6-h-2a

    • 3-6-h-2b

    • 3-6-h-2c

    • 3-6-h-2d

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    31 mark

    Compound K, C5H12O, is oxidised by acidified sodium dichromate (VI) to compound L.

    Compound L reacts with butan-2-ol in the presence of a little concentrated sulfuric acid to give liquid M.

    What could be the formula of liquid M?

    • (CH3)2CHCH2CO2C(CH3)3

    • CH3(CH2)3CO2(CH2)3CH3

    • CH3(CH2)3CO2CH(CH3)CH2CH3

    • CH3(CH2)2CO2CH2CH2(CH3)2

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    41 mark

    Compound X can be made from 2-hydroxybutanoic acid.

    3-6-h-4

    What should be heated with 2-hydroxybutanoic acid in order to make compound X?

    • Aluminium oxide

    • Concentrated sulfuric acid

    • Dilute sodium hydroxide

    • Acidified potassium manganate under reflux

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    51 mark

    Oxaloacetic acid can be synthesised from fumaric acid in a two-step process involving the intermediate Z.

    HO subscript 2 CCH equals CHCO subscript 2 straight H space space rightwards arrow with step space 1 on top space space bold Z space space rightwards arrow with step space 2 on top space space HO subscript 2 CCOCH subscript 2 CO subscript 2 straight H space space space space space space space space fumaric space acid space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space oxaloacetic space acid

     

    Each step involved can be achieved in the laboratory by a single reagent. 

    What could be the intermediate Z and the reagent for step 2?

     

    Z

    Reagent for step 2

    A

    B

    C

    D

    HO2CCH(OH)CH2CO2H

    HO2CCH(OH)CH2CO2H

    HO2CCHBrCH2CO2H

    HO2CCHBrCH(OH)CO2H

    Fehling’s solution

    Warm acidified K2Cr2O7

    Warm acidified KMnO4

    Warm NaOH (aq)

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      61 mark

      Use of the Periodic Table is relevant to this question.

      During a lesson, a teacher heated ethyl propanoate under reflux with aqueous sodium hydroxide. The two organic products are then separated, purified and weighed.

      Out of the total mass of products obtained, what is the percentage by mass of each product?

      • 50.0 % and 50.0 %

      • 57.7 % and 42.3 %

      • 61.7 % and 38.3 %

      • 67.6 % and 32.4 %

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      71 mark

      Citric acid gives lemons and other citrus fruits their sour taste.

      HO2CCH2C(OH)(CO2H)CH2CO2H

              citric acid

      What is the volume of 0.2 mol dm–3 sodium hydroxide solution required to neutralise a solution containing 0.008 mol of citric acid?

      • 40 cm3

      • 80 cm3

      • 120 cm3

      • 160 cm3

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      81 mark

      The compound 2-ethyl-3-methylbutanoic acid gives rum it’s signature smell.

      3-6-h-8

      Which compound will produce 2-ethyl-3-methylbutanoic acid by heating under reflux with alcoholic sodium cyanide and subsequent acid hydrolysis of the reaction product?

      • 3-6-h-8a

      • 3-6-h-8b

      • 3-6-h-8c

      • 3-6-h-8d

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      91 mark

      Digestion of various foods and medicines can cause acidic compounds to pass through the body. The stomach wall can become sensitive to acidic compounds, resulting in stomach ulcers.

      Which of the following is the most acidic compound?

      • 3-6-h-9a

      • 3-6-h-9b

      • 3-6-h-9c

      • 3-6-h-9d

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      101 mark

      Use of the Period Table is relevant to this question.

      30 g of an alcohol and 30 g of a carboxylic acid are heated under reflux together to produce 33 g of propyl butanoate.  

      What is the yield of the ester?

      • 25 %

      • 38 %

      • 50 %

      • 66 %

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