Aromatic Chemistry (AQA A Level Chemistry): Exam Questions

Exam code: 7405

3 hours30 questions
11 mark

What are the reagents required for the conversion of benzene to nitrobenzene?

  • Hydrogen gas in presence of nickel catalyst

  • Concentrated nitric acid and concentrated hydrochloric acid

  • Concentrated sulfuric acid and concentrated nitric acid

  • Tin with concentrated hydrochloric acid

21 mark

Cyclohexene is an unsaturated hydrocarbon and can undergo hydrogenation as shown 

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The expected value for the enthalpy value for the hydrogenation of benzene is -360 kJ mol-1. The actual value for the reaction is -208 kJ mol-1.

Which is the correct explanation? 

  • The s orbitals overlap to produce a stable structure

  • The bond length of the C=C bonds are shorter than the C-C bonds

  • Delocalisation of electrons in the benzene ring increases the stability

  • Each carbon in benzene has three covalent bonds

31 mark

The correct equation for the generation of an electrophile formed in Friedel-Crafts alkylation is

  • CH3CH2Cl + AlCl3 → CH3CH2+ + AlCl4- 

  • HNO3 + 2H2SO4  → NO2+ + 2HSO4- + H3O+

  • AlCl 4- + H+  → AlCl 3 + HCl 

  • CH3COCl + AlCl3 → CH3CO+ + AlCl4- 

41 mark

Which part of the following mechanism is not correct?

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    51 mark

    Which product is formed when benzene, C6H6, reacts with ethanoyl chloride, CH3COCl, in the presence of aluminium chloride, AlCl3?

    • C6H6COCH3

    • HCl

    • C6H5CH3CO

    • C6H5CH2CH3

    11 mark

    Benzene can undergo nitration to form nitrobenzene. Which of the following statements is not correct?

    • Concentrated nitric acid acts as a base

    • A nitronium ion acts as an electrophile

    • HSO4- is produced in the formation of the electrophile

    • Aluminum chloride is required as a catalyst for the reaction

    21 mark

    Which of the following reagents would be suitable for the reduction of nitrobenzene to produce phenylamine?

    • LiAlH4 in dry ether

    • NaBH4

    • Fe in presence of HCl

    • H2 in presence Mg catalyst

    31 mark

    A student reacted 2.5 g of methylbenzene, C6H5CH3, with one mole of bromine, Br2, in the presence of aluminium bromide, AlBr3

    The mass of the organic product formed is

    • 6.8 g

    • 2.2 g

    • 4.6 g

    • 4.7 g

    41 mark

    Which of the following is correct?

           

    Bond angles present in cyclohexene

    A

    109.5 o only

    B

    109.5 o and 120 o

    C

    120 o only

    D

    109.5 o and 107 o

      51 mark

      Which of the following explains why the enthalpy of hydrogenation of benzene is lower than expected?

      • The overlap of p-orbitals allows electrons to become delocalised

      • Benzene contains both single and double bonds

      • The carbon-carbon bond lengths in benzene are shorter than a carbon-carbon single bond

      • Benzene contains sp2 hybridised carbon atoms

      11 mark

      Which statement correctly explains the difference between the enthalpy change for the hydrogenation of cyclohexa-1,4-diene and the hydrogenation of cyclohexa-1,3-diene?

      • Cyclohexa-1,4-diene is less stable than cyclohexa-1,3-diene

      • Cyclohexa-1,4-diene is more stable than cyclohexa-1,3-diene

      • There is greater overlap of pi bonds in cyclohexa-1,4-diene

      • The C=C double bonds are closer together cyclohexa-1,3-diene which creates repulsion

      21 mark

      Propene reacts with benzene in the presence of aluminium chloride and hydrogen chloride.

      What are the most likely products of this reaction?

      • C6H5CH2CH2CH3, AlCl3 and HCl 

      • C6H5CH(CH3)2, AlCl3 and HCl 

      • C6H5COCH2CH3, AlCl3 

      • C6H5CH2CH3, AlCl3 and HCl 

      31 mark

      Which statement about the reactions of benzene is correct?

      • Ammonia is not a strong enough nucleophile to undergo nucleophilic substitution with benzene 

      • During electrophilic substitution, the electrophile attacks the delocalised electrons in the benzene ring 

      • Addition reactions do not require delocalised electrons to form new bonds

      • The delocalised system in benzene will repel attack from a nucleophile 

      41 mark

      Which product(s) are formed when the theoretical compound cyclohexa-1,3,5-triene reacts with one molecule of bromine?

      7-4-h-q4-aqa-al-chemistry-mcq
        51 mark

        Compound B, C8O3H7N, is formed in two steps from benzene. What are the possible steps for the formation of compound B.

         

        Step 1

        Step 2

          A    

        AlCl3 and CH3COCl

        Conc HNO3 and H2SO4

        B

        Conc HNO3 and H2SO4

        AlCl3, HCl, and C2H4

        C

        Conc HNO3 and H2SO4

        Sn, conc HCl and NaOH

        D

        AlCl3 and CH3COCl

        Sn, conc HCl and NaOH