Carbonyl Compounds - exam practice
Carbonyl Compounds
Question 1 of 12
The diagram below shows a compound containing an aldehyde functional group.
Describe a suitable chemical test, including the observation that would be made, to identify the aldehyde functional group in this compound.
Outline a mechanism for the reaction shown in the diagram below.
Name the product formed in the reaction in part b).
This question is about the aldehyde ethanal.
Describe the test for an aldehyde and give the result.
Name the reagent that is needed to convert ethanal into ethanol.
Outline the mechanism for the reaction between ethanal and KCN/H+.
The product formed in the reaction in part c) is a racemic mixture.
State the meaning of the term racemic mixture.
Explain why a racemic mixture forms in the reaction of ethanal with KCN/H+.
The flowchart below shows the synthesis of a hydroxynitrile from butan-2-ol.
Give the reagent(s) and conditions required for step 1.
Give a chemical test, and the observation that would be made, to identify the carbonyl group in the product of step 1.
Give a chemical test, and the observation that would be made, to identify the CH3CO group in the product of step 1.
In step 2, butanone undergoes an addition reaction with CN- ions.
Outline the mechanism for this reaction.
Name the product formed in part d).
Explain why the product in part d) has no effect on plane polarised light.
Propanone reacts with HCN and dilute acid to form a hydroxynitrile. The reaction is usually carried out with KCN instead of HCN.
Suggest why KCN is used instead of HCN.
Outline the mechanism for the reaction of propanone with KCN and dilute acid.
Explain why the reaction in part b) does not produce a racemic mixture.
Which of the following compounds produces a racemic mixture when reacted with KCN and dilute acid?
Pentanal reacts with KCN and dilute acid to form a racemic mixture of two stereoisomers.
Outline a mechanism for the reaction of pentanal with KCN and dilute acid.
Name the product formed in part a).
Describe how you could distinguish between separate samples of the two stereoisomers formed in the reaction in part a).
An isomer of pentanal reacts with KCN and dilute acid to produce a compound that doesn't show stereoisomerism.
Draw the structure of this compound.
Explain why the compound drawn in part d) does not show stereoisomerism.
Butanone can be reduced using sodium borohydride, NaBH4, and dilute acid.
Write an overall equation for the reduction, using [H] to represent the reducing agent.
Explain why the product of the reduction in part a) has no effect on plane polarised light.
Refer to the mechanism of the reaction in your answer.
Which of the following alcohols could not be produced by the reduction of an aldehyde or ketone?
Outline a mechanism for the reaction of (CH3)2CHCHO with KCN and dilute acid.
Name the product formed in part a).
The reaction in part a) produces a pair of optical isomers.
Draw the structures of these isomers.
Butanone can be reduced using lithium aluminium hydride, LiAlH4, in dry ether.
Write an overall equation for the reduction, using [H] to represent the reducing agent.
Explain why the product of the reduction in part a) has no effect on plane polarised light.
Refer to the mechanism of the reaction in your answer.
Which of the following alcohols could not be produced by the reduction of an aldehyde or ketone?
But-2-enal has the structural formula CH3CH=CHCHO.
Describe a chemical test, and give the observation that would be made, to confirm that but-2-enal is an aldehyde.
Draw the skeletal formula of the product that would form when but-2-enal is reacted with LiAlH4.
Name the type of reaction occurring in part b).
Butanal and butanone both react with 2,4-DNPH to produce a yellow precipitate.
Outline how the precipitates can be used to distinguish between the two carbonyl compounds.
The diagram below shows the structures of the compounds cinnamaldehyde and methylcinnamaldehyde.
Describe a chemical test, and give the observation that would be made, to confirm that both compounds contain an aldehyde functional group.
Describe a chemical test, and give the observation that would be made, to confirm the presence of a carbonyl group in both compounds.
Include how the two compounds could be distinguished.
Complete the diagram below to show the structure of the product formed when cinnamaldehyde is reacted with LiAlH4.
Complete the diagram below to show the structure of the product formed when methylcinnamaldehyde is reacted with KCN and dilute acid.
The following three carbonyl compounds are structural isomers of C5H10O2.
Describe chemical tests that you could carry out in test-tubes to distinguish between compounds A, B and C.
Include appropriate reagents and any relevant observations. Also include equations showing structures for the organic compounds involved.
Describe a chemical test to confirm that cinnamaldehyde and methylcinnamaldehyde contain a carbonyl group.
How could the products of this test be used to distinguish between the two compounds?
Your answer should not include spectroscopy.
Maleic acid is a stereoisomer of fumaric acid. The structure of the two acids are shown below.
Describe chemical tests that can be carried out in a laboratory to identify the two functional groups in both acids.
Give the empirical formula of both acids.
State what type of geometric isomer maleic acid is.
Explain why maleic acid and fumaric acid are different compounds.
The structures of three organic compounds A, B and C are shown.
These compounds can be distinguished by simple test-tube reactions.
Give a reagent (or combination of reagents) that could be added separately to compounds A and B to distinguish between them.
State what is observed in each case.
Give a reagent (or combination of reagents) that could be added separately to compounds A and C to distinguish between them.
State what is observed in each case.
Give the steps to show how 2,4-dinitrophenylhydrazine could be used to distinguish between compounds A and C.