Alcohols (CIE A Level Chemistry)

Exam Questions

2 hours36 questions
11 mark

Compound X produces a carboxylic acid when heated under reflux with acidified potassium dichromate (VI). Compound X has no reaction with sodium metal.

What could be the identity of compound X?

  • Propanal

  • Propanone

  • Propan-1-ol

  • Propan-2-ol

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21 mark

Considering only structural isomers, what is the number of alcohols of each type with the formula C5H12O?

 

Primary

Secondary

Tertiary

A

B

C

D

3

4

4

5

3

2

3

2

2

2

1

1

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    31 mark

    Which sequence of reagents may be used in the laboratory to convert propan-1-ol into 1-bromopropane?

    • Concentrated sulfuric acid, followed by bromine

    • Concentrated sulfuric acid, followed by potassium bromide

    • Ethanolic sodium hydroxide, followed by bromine

    • Ethanolic sodium hydroxide, followed by potassium bromide

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    41 mark

    Which diagram gives the skeletal formula of 4-chloropentan-2-ol?

    • 3-4-e-3a

    • 3-4-e-3b

    • 3-4-e-3c

    • 3-4-e-3d

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    51 mark

    Which alcohol has a chiral centre and can be oxidised to a ketone?

    • Pentan-2-ol

    • Pentan-3-ol

    • 3-methylhexan-1-ol

    • 3-methylhexan-3-ol

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    61 mark

    Which reaction will distinguish between a primary and a secondary alcohol?

    • Warming with H+ / MnO4-

    • Warming with H+ / Cr2O72-

    • Dehydration, followed by reaction with Br2 (aq)

    • Oxidation, followed by reaction with Fehling’s (or Tollens’) reagent

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    71 mark

    An alcohol with molecular formula CnH2n+1OH has a chiral carbon atom but does not react with hot, acidified K2Cr2O7.

    What is the smallest possible value for n?

    • 5

    • 6

    • 7

    • 8

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    81 mark

    Buta-1,3-diene is currently obtained from fossil fuel sources. In future it may be obtained from ethanol, which can be produced from non-food agricultural crops. The sequence of reactions is as follows.

    3-4-e-10

    Which term could be used to describe step 1?

    • Condensation

    • Dehydration

    • Dehydrogenation

    • Hydrogenation

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    91 mark

    The functional group in a primary alcohol is –CH2OH.

    Which reagent reacts with a primary alcohol, under suitable conditions, to give an organic product with the same number of oxygen atoms as the alcohol?

    • Al2O3

    • CH3CO2H

    • HBr

    • Na

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    11 mark

    Which isomer of C4H10O forms three alkenes on dehydration?

    • Butan-1-ol

    • Butan-2-ol

    • 2-methylpropan-1-ol

    • 2-methylpropan-2-ol

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    21 mark

    Primary alcohols can be oxidised to aldehydes using either acidified potassium dichromate (VI) or acidified potassium manganate (VII). Both these oxidising agents change colour as they are reduced.

    What is the colour of each oxidising agent before and after it has reacted?

     

    Acidified potassium dichromate (VI)

    Acidified potassium manganate (VII)

     

    Before

    After

    Before

    After

    A

    B

    C

    D

    Green

    Orange

    Orange

    Purple

    Orange

    Green

    Green

    Colourless

    Purple

    Colourless

    Purple

    Orange

    Colourless

    Purple

    Colourless

    Green

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      31 mark

      Lactic acid, CH3CH(OH)CO2H, causes pain when it builds up in muscles.

      Which reagent reacts with both of the –OH groups in lactic acid?

      • Acidified potassium dichromate (VI)

      • Ethanol

      • Sodium

      • Sodium hydroxide

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      41 mark

      Which reagent could detect the presence of alcohol in a petrol consisting mainly of a mixture of alkanes and alkenes?

      • Na

      • Br2 (in CCl4)

      • KMnO4 (aq)

      • 2,4-dinitrophenylhydrazine

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      51 mark

      Which reagent reacts with ethanol and also reacts with ethanoic acid?

      • Acidified potassium dichromate (VI)

      • Sodium

      • Sodium carbonate

      • Sodium hydroxide

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      61 mark

      Prop-2-en-1-ol, also known as allyl alcohol, reacts to form a product that can exist as optical isomers. 

      Which reagent would produce optical isomers from allyl alcohol?

      • Phosphorus pentachloride

      • Sodium

      • Bromine

      • Hydrogen and nickel

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      71 mark

      In its reaction with sodium, 1 mol of a compound X gives 1 mol of H2 (g). 

      Which compound might X be?

      • CH3CH2CH2CH2OH

      • (CH3)3COH

      • CH3CH2CH2CO2H

      • CH3CH(OH)CO2H

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      81 mark

      Which volume of oxygen measured at room temperature and pressure is needed for the complete combustion of 0.1 mol of propan-1-ol?

      • 10.8 dm3

      • 12.0 dm3

      • 21.6 dm3

      • 24.0 dm3

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      91 mark

      2.30 g of ethanol was mixed with aqueous acidified potassium dichromate (VI) and the desired organic product was collected by immediate distillation under gentle warming. The yield of the product was 70.0%.

      What mass of product was collected?

      • 1.54 g

      • 1.61 g

      • 2.10 g

      • 2.20 g

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      101 mark

      Which alcohol gives only one possible oxidation product when warmed with dilute acidified potassium dichromate (VI)?

      • Butan-1-ol

      • Butan-2-ol

      • 2-methylpropan-1-ol

      • 2-methylpropan-2-ol

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      111 mark

      The compound ‘leaf alcohol’ is partly responsible for the smell of new-mown grass.

                                                     CH3CH2CH=CHCH2CH2OH

                                                                  leaf alcohol

      What will be formed when ‘leaf alcohol’ is oxidised using an excess of hot, acidified K2Cr2O7 (aq)?

      • CH3CH2CH(OH)CH(OH)CH2CO2H

      • CH3CH2COCOCH2CO2H

      • CH3CH2CH=CHCH2CO2H

      • CH3CH2CO2H and HO2CCH2CO2H

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      11 mark

      An organic compound J reacts with sodium to produce an organic ion with a charge of –3. 

      J reacts with NaOH (aq) to produce an organic ion with a charge of –1. 

      What could be the structural formula of J?

      • HO2CCH(OH)CH2CO2H

      • HO2CCH(OH)CH2CHO

      • HOCH2CH(OH)CH2CO2H

      • HOCH2COCH2CHO

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      21 mark

      In a multi-step synthesis reaction, butanal is converted into a compound Z.

      begin mathsize 16px style C H subscript bold 3 bold open parentheses C H subscript bold 2 bold close parentheses subscript bold 2 C H O space space rightwards arrow with H C N comma space Na C N on top space space italic X bold space space rightwards arrow with hot space dilute space H subscript 2 S O subscript 4 on top space space Y bold space space rightwards arrow with space trace space of space conc point space H subscript 2 S O subscript 4 below and C H subscript 3 C H subscript 2 O H comma space heat on top space space italic Z end style

      What could Z be?

      • CH3(CH2)3COOCH2CH3

      • CH3(CH2)2CH(OH)COOCH2CH3

      • CH3(CH2)CH(OH)COCH2CH3

      • CH3(CH2)2CH(OCH2CH3)COOH

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      31 mark

      What will react differently with the two isomeric alcohols, (CH3)3CCH2OH and (CH3)2CHCH2CH2OH?

      • Sodium

      • Acidified aqueous potassium dichromate (VI)

      • Phosphorus pentachloride

      • Concentrated sulfuric acid

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      41 mark

      Compound Q has the molecular formula C10H14O and is unreactive towards mild oxidising agents.

      Which structure formed by the dehydration  of compound Q?

      • 3-4-h-8a

      • 3-4-h-8b

      • 3-4-h-8c

      • 3-4-h-8d

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      51 mark

      The foul smell that skunks spray is due to a number of thiols, one of which is methanethiol, CH3SH, which burns as follows.

      CH3SH + 3O2 rightwards arrow CO2 + SO2 + 2H2O

      A sample of 15 cm3 of methanethiol was exploded with 90 cm3 of oxygen.

      What would be the final volume of the resultant mixture of gases when cooled to room temperature?

      • 30 cm3

      • 45 cm3

      • 75 cm3

      • 105 cm3

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      61 mark

      1.50 g of butan-2-ol were mixed with excess acidified potassium dichromate (VI). The reaction mixture was then boiled under reflux for fifteen minutes. The organic product was then collected by distillation. The yield of product was 80.0%.

      What mass of product was collected?

      • 0.91 g

      • 1.17 g

      • 1.43 g

      • 1.46 g

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