AQA AS Chemistry

Topic Questions

3.5 Alcohols

11 mark

Which reagents could be used in the laboratory to convert ethan-1-ol into ethene and water?

  • Potassium hydroxide in ethanol 

  • Aluminium oxide and concentrated phosphoric acid

  • Concentrated sulfuric acid with hydrogen bromide

  • Potassium hydroxide in a 50:50 ethanol and water

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21 mark

What is the correct name and classification of alcohol for the following compound?

q2-3-5-easy-mcq-alcohols

 

IUPAC name

Classification

A

2-chloropentan-3-ol

Tertiary

B

2-chloropentan-3-ol

Secondary

C

3-chloropentan-2-ol

Tertiary

D

3-chloropentan-2-ol

Secondary

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31 mark

What can be produced when an aqueous solution of butan-2-ol is fully oxidised under suitable conditions?

  • Butanone

  • Butanal

  • Butanoic acid

  • Butyl butanoate 

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41 mark

Which structure shows a primary alcohol that cannot be dehydrated to form an alkene?

  • CH3OH

  • CH3CH2OH

  • CH3CH(OH)CH3

  • CH3CH3CH2OH

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51 mark

Which alcohol can be oxidised to form a carboxylic acid?

  • Butan-2-ol

  • Pentan-3-ol

  • 3-methylhexan-1-ol

  • 3-methylhexan-3-ol

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61 mark

Which of the following statements about the production of ethanol is not correct? 

  • Producing bioethanol from cereal crops via fermentation of glucose is a carbon neutral process

  • Hydration of ethene to produce ethanol requires a phosphoric acid catalyst 

  • Ethanol and carbon dioxide are the products of fermentation of glucose

  • The reaction between ethene and steam to produce ethanol is an example of an electrophilic addition reaction 

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71 mark

What is the correct equation for the complete combustion of butanol?

  • C4H9OH + 3O2 → 2CO2 + H2O

  • C4H9OH + 9.5O2 → 4CO + 5H2O

  • C4H9OH + 6O2 → 4CO2 + 5H2O

  • C4H9OH + 8O2 → 4CO + 5H2O

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81 mark

Which of the following equations for the oxidation of an alcohol is correct?

  • CH3CH(OH)CH3 + [O] → CH3CH2COOH + H2O

  • CH3CH(OH)CH3 + [O] → CH3COCH3 + H2O

  • CH3CH(OH)CH3 + [O] → CH3CH2CHO + H2O

  • CH3CH(CH3)(OH)CH3 + H+ → CH3C(CH3)CH2 + H2O

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91 mark

When butan-1-ol reacts to produce an alkene an elimination reaction occurs. What is the first step of the mechanism for this reaction?

  • Curly arrow from lone pair on O atom in butan-1-ol to H+ 

  • Curly arrow from H+ to OH group in butan-1-ol

  • Curly arrow from lone pair on H atom in butan-1-ol to H+

  • Curly arrow from H+ to H atom in OH group in butan-1-ol

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101 mark

Which statement about the reactions of alcohols and aldehydes is not correct?

  • K2Cr2O7 can oxidise secondary alcohols 

  • The reduction of an aldehyde produces a primary alcohol

  • The oxidation of an aldehyde produces a carboxylic acid

  • Aldehydes turn Fehling’s solution from brick red to blue 

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11 mark

What is the correct name and classification of the alcohol below?

q1-3-5-hard-mcq-alcohols

 

IUPAC name

Classification

A

2-methyl-3-ethylpropan-1-ol

Primary

B

3-methyl-2-ethylpropan-1-ol

Primary

C

2,2-dimethylpentan-5-ol

Secondary

D

3,3-dimethylpentan-1-ol

Primary

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21 mark

Compound K is produced in the following reaction pathway

q2-3-5-hard-mcq-alcohols

In Step 1, C4H9Cl  reacts with aqueous sodium hydroxide to form compound J

Compound J is fully oxidised by acidified potassium dichromate(VI) to form compound K

When compound K is reacted with calcium carbonate, effervescence is observed.

What could be the formula of compound J?

  • CH3CH2C(OH)CH3

  • CH3C(CH3)(OH)CH3

  • CH3CH2CH2CH2OH

  • CH3CH2CH2COOH

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31 mark

Compound X is a hydrocarbon and can be formed from CH3CHBrCH3 or CH3CH(OH)CH3.

Which of the statements about the reaction scheme is correct?

q3-3-5-hard-mcq-alcohols

  • Compound X exhibits geometric isomerism 

  • Reaction 1 requires ethanolic, concentrated sodium hydroxide and reflux

  • Reaction 2 requires concentrated acid

  • Reaction 3 requires aqueous sodium hydroxide and reflux

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41 mark

Which of the following compounds is not oxidised under mild oxidising conditions?

  • 4-hydroxypentan-2-one

  • Cyclohexane-1,2-diol 

  • 3-hydroxy-4-methylpentanal

  • 4-hydroxy-4-methylpentanoic acid 

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51 mark

Which statement about tertiary alcohols is correct?

  • Tertiary alcohols cannot be oxidised as there are no hydrogen atoms in a C-H bond available to break

  • Tertiary alcohols form a green solution when reacted with acidified potassium dichromate  

  • 2-hydroxy-3-methylbutane is classed as a tertiary alcohol 

  • Primary alcohols undergo a dehydration reaction easier than tertiary alcohols

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61 mark

What is the correct equation for the reaction between K2Cr2O7 and ethanol?

  • C2H5OH + [O] → C2H4 + H2O

  • 3C2H5OH + 2Cr2O72- + 16H+ → 3CH3COOH + 4Cr3+ + 11H2O

  • C2H5OH + [H] → CH3COOH + H2O

  • Cr2O72- + 16H+ + 8e- → 2Cr3+ + 7H2

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71 mark

Which of the following conditions is not required during the preparation of propanal from propan-1-ol?

  • Excess propan-1-ol

  • Excess concentrated, acidified potassium dichromate(VI) solution 

  • Distil the product off as soon as it is produced

  • Perform the reaction below the boiling point of propan-1-ol

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81 mark

How many possible structural isomers and stereoisomers are produced during the dehydration of butan-2-ol?

  • 2

  • 3

  • 4

  • 5

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91 mark

What is the correct equation for the oxidation of prop-2-ene-1-ol reacts with acidified potassium dichromate(VI)?

  • CH2CHCH2OH + [O] → HOCCHCH2 + H2O

  • HOCH2CH2CH3 + [O] → HOCCH2CH3 + H2O

  • HOCH2CH2CH3 + [O] → HOCCH2CH3

  • CH2CHCH2OH + [O] → H2C(OH)CH(OH)CHO + H2O

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101 mark

Use the information in the table to identify compound X.

Low temperature required to form a compound which turns bromine water colourless

Sweet smelling liquid produced when reacted with ethanoic acid

Relative molecular mass of 88.0 g mol-1

  • 2-methylbutan-3-ol

  • Pentan-3-ol

  • Pentan-2-one

  • 2-methylbutan-2-ol

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11 mark

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

  • pentan-2-ol

  • pentan-1-ol

  • 2-methylbutan-1-ol

  • 2-methylbutan-2-ol

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21 mark

Which reaction would not give propene?

  • adding excess hot concentrated sulfuric acid to propan-1-ol

  • adding warm aqueous sodium hydroxide to 2-bromopropane

  • adding warm ethanolic sodium hydroxide to 1-bromopropane

  • passing propan-2-ol vapour over heated aluminium oxide

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31 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=CHCH2COH

  • CH3CH2CH=CHCH2CO2H

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41 mark

Which of the following compounds gives a positive response to Fehling’s solution and can also be oxidised by acidified dichromate(VI) solution?

  • CH3COCH2CHO

  • CH3COCH2CH2OH

  • CH3CH2COOCH3

  • CH3CH2CH2COOH

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51 mark

Hydroxyethanal has the structural formula HOCH2CHO.

In an experiment hydroxyethanal is heated under reflux with an excess of acidified potassium dichromate(VI) until no further oxidation takes place.

Which functional group will be formed in the product? 

  • ketone

  • alcohol 

  • carboxylic acid

  • aldehyde

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61 mark

Which equation is not a reaction for the formation of ethanol?

  • CH3CH2Cl + OH- → CH3CH2OH + Cl-

  • C2H4 + H2O → CH3CH2OH

  • C6H12O6 → 2CH3CH2OH + 2CO2

  • CH3CH2CN + H2O → CH3CH2OH + HCN

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71 mark

Which of the following statements is correct about the production of bioethanol from cereal crops?

  • Harvesting and processing the crops is carbon neutral

  • Using bioethanol reduces the consumption of petrol and diesel made from crude oil 

  • Transportation of bioethanol is considered carbon neutral

  • The manufacture and use of fertilisers contributes to the carbon footprint of growing crops

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81 mark

Pentan-1-ol is a primary alcohol which can undergo oxidation. Which of the following compounds cannot be produced by the oxidation of pentan-1-ol?

  • Pentan-2-one

  • Pentanal

  • Pentanoic acid

  • Carbon dioxide

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91 mark

Which of the following is correct when Compound A reacts to form a tertiary alcohol?

q9-3-5-medium-mcq-alcohols

 

Reagent

Solvent

Condition

A

H3PO4

Water

300 °C

B

NaOH

Water

Room temperature

C

H3PO4

Ethanol

300 °C

D

NaOH

Ethanol

Room temperature

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101 mark

The curly arrow in the diagram shows the first step in the dehydration of butan-1-ol to give but-1-ene

What are the next two steps in the mechanism?

q10-3-5-medium-mcq-alcohols

 

Second step

Third step

A

Curly arrow from positively charged oxygen atom to C-O bond

Curly arrow from C-H bond to C-C bond

B

Curly arrow from positively charged oxygen atom to C-O bond

Curly arrow from C-H bond to H+ ion

C

Curly arrow form C-O bond to positively charged oxygen atom

Curly arrow from C-H bond to C-C bond

D

Curly arrow from O-H bond to O atom

Curly arrow from C-C bond to C-C bond containing carbocation

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