Syllabus Edition

First teaching 2023

First exams 2025

|

Characteristic Organic Reactions (CIE AS Chemistry)

Exam Questions

1 hour15 questions
11 mark

Which pairs of homologous series do not have the same C:H ratio in their general formulae?

  • Aldehydes and ketones

  • Alkanes and alkenes

  • Carboxylic acids and esters

  • Alkenes and aldehydes

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21 mark

The following mechanism shows hydrogen cyanide reacting with propanone.

3-1-e-3

Which of the following statements is incorrect?

  • Heterolytic bond breaking is involved.

  • CN- is an electrophile.

  • This is an addition reaction.

  • Propanone is a ketone.

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31 mark

Which of the following statements correctly describes ‘electrophilic addition’?

  • The organic molecule acts as a nucleophile and becomes more saturated.

  • The organic molecule acts as an electrophile and becomes more saturated.

  • The organic molecule acts as a nucleophile and becomes less saturated.

  • The organic molecule acts as an electrophile and becomes less saturated.

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41 mark

Which of these compounds would act as a nucleophile?

  • C2H6

  • H+

  • OH-

  • Cl

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11 mark

1-chloroethane, CH3CH2Cl and NaOH (aq) are reagents in a reaction. 

Which row correctly describes what type of reaction this would be?

  • Nucleophilic addition

  • Nucleophilic substitution

  • Electrophilic addition

  • Electrophilic substitution

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21 mark

Which features about the members of a homologous series are correct?

 

All members have the same general formula

The members have similar chemical properties

The members show a gradual change in physical properties

A

B

C

D

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    31 mark

    Which diagram shows the heterolytic fission of the C-Cl bond to form a carbocation and Cl?

    • ocr-as-4-1m-mcq-q9-heterolytic-fission-of-chloropropane-cl

    • ocr-as-4-1m-mcq-q9-heterolytic-fission-of-chloropropane-cl-

    • ocr-as-4-1m-mcq-q9-heterolytic-fission-of-chloropropane-2--ve-ions

    • ocr-as-4-1m-mcq-q9-homolytic-fission-of-chloropropane

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    11 mark

    The reaction sequence below shows a pair of reaction types. 

    3-1-h-2

    Which row in the table correctly shows the two reaction types?

     

    Reaction 1

    Reaction 2

    A

    Nucleophilic addition

    Nucleophilic substitution

    B

    Electrophilic addition

    Electrophilic substitution

    C

    Nucleophilic addition

    Electrophilic substitution

    D

    Electrophilic addition

    Nucleophilic substitution 

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      21 mark

      The methyl group, CH3, can exist as an anion, a cation or a free radical. Molecules that contain a methyl group can act as a nucleophile, an electrophile or a free radical depending on the number of outer shell electrons on the methyl carbon atom.

      How many outer shell electrons must be present for CH3 to act in these different ways?

       

      CH3 as a nucleophile

      CH3 as a electrophile

      CH3 as a free radical

      A

      6

      8

      7

      B

      8

      6

      7

      C

      6

      7

      8

      D

      8

      7

      6

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        31 mark

        Which of the following statements about nucleophiles and electrophiles are always true? 

         

        Nucleophile

        Electrophile

        A

        Has a lone pair of electrons

        Accepts a pair of electrons

        B

        Is a negative ion

        Is a positive ion

        C

        Attacks double bonds

        Is only involved in substitution reactions

        D

        Accepts a pair of electrons

        Has a lone pair of electrons

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