AQA A Level Chemistry

Topic Questions

7.9 Organic Mechanisms (A Level only)

11 mark

Ethanol can react to form ethene in the presence of concentrated sulfuric acid, H2SO4, at 300 ℃.

Which of the following descriptions is correct for the first mechanism arrow?

  • From :OH to H in H2SO4

  • From C-O bond to positively charged O atom

  • From H in H2SO4 to :OH 

  • From H-C bond to C-C bond 

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21 mark

Which mechanism does not occur in the following reaction sequence?

7-9-e-q2-mcq-aqa-al-chemistry

  • Nucleophilic addition

  • Nucleophilic substitution 

  • Nucleophilic addition elimination

  • Free radical substitution 

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31 mark

Which mechanism occurs when potassium cyanide, KCN, reacts with an aldehyde?

  • Nucleophilic substitution

  • Nucleophilic addition

  • Electrophilic substitution

  • Nucleophilic addition elimination 

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41 mark

Which mechanism occurs between phenylamine and chloroethane?

  • Electrophilic substitution 

  • Free radical substitution 

  • Nucleophilic addition elimination 

  • Nucleophilic substitution 

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51 mark

Which of the arrows in the following mechanism is not correct?

7-9-e-q5-mcq-aqa-al-chemistry

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11 mark

Which alkene reacts with hydrogen chloride to give 2-chloro-3-methylpentane as the major product?

  • CH3CH2C(CH3)=CHCH3

  • CH3CH2CH2CH=CHCH3

  • CH3CH2C(CH3)=CH2

  • CH3CH2CH(CH3)CH=CH2

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21 mark

Some compounds form racemic mixtures when potassium cyanide, KCN (aq), and dilute hydrochloric acid, HCl (aq), are added.

Which of the below will form a racemic mixture?

  • HCHO

  • (CH3)2CO

  • CH3CH2CHO

  • (C3H7)2CO

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31 mark

The reaction between butanoyl chloride, CH3CH2CH2COCl, and benzene, C6H6, is an example of acylation.

Which of the following correctly demonstrates part of the reaction mechanism?

  • 7-9-h-q3-a-mcq-aqa-al-chemistry

  • 7-9-h-q3-b-mcq-aqa-al-chemistry

  • 7-9-h-q3-c-mcq-aqa-al-chemistry

  • 7-9-h-q3-d-mcq-aqa-al-chemistry

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41 mark

A mixture of products are made when methylamine, CH3NH2, and chloroethane, CH3CH2Cl, react by nucleophilic substitution.

Which of the following is not a possible product?

  • C2H5NHCH3

  • (C2H5)2NCH3

  • [(C2H5)3NCH3]⁺Cl

  • [(C2H5)2N(CH3)2]⁺Cl

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51 mark

4-methylphenylamine is formed during the following reaction scheme.

Which combination of reagents are required for each step?

7-9-h-q5-mcq-aqa-al-chemistry

 

Step 1

Step 2

A

Conc H2SO4 and conc HCl

Ni and H2,

B

Conc H2SO4 and conc HNO3

Sn and conc HCl

C

Conc H2SO4 and conc HNO3

NaBH4 and conc HCl

D

Conc HNO3 and conc HCl

Sn and conc H2SO4,

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11 mark

In the mechanism shown, which of the arrows is not correct?

7-9-m-q1-mcq-aqa-al-chemistry

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21 mark

In the reaction scheme outlined, which mechanism occurs in Step 1?

7-9-m-q2-mcq-aqa-al-chemistry

 

  • Elimination

  • Nucleophilic addition 

  • Nucleophilic substitution 

  • Electrophilic addition 

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31 mark

Propanone can be used to form 2-hydroxy-2-methylpropanenitrile.

Which of the following descriptions is correct for the first two mechanism arrows?

 

Arrow 1

Arrow 2

A

From :OH- nucleophile to δ+ C atom

From δ- O atom bond to C=O atom

B

From :CN- nucleophile to δ- C atom

From lone pair on O atom to H+ ion

C

From :CN- nucleophile to δ+ C atom

From C=O bond to δ- O atom

D

From :OH- nucleophile to δ- C atom

From δ- O atom bond to C=O atom

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41 mark

The products formed from the reaction between butan-1-ol with ethanoic anhydride are

  • Water and ethyl butanoate 

  • Ethanoic acid and butyl ethanoate 

  • Water and butyl ethanoate

  • Ethanoic acid and ethyl butanoate

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51 mark

Which equation does not represent the formation of an electrophile?

  • CH3CH2Cl + AlCl3 → CH3CH3+ + AlCl4-

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

  • CH3COCl + AlCl3 → CH3CO+ + AlCl4-

  • CH3Br + AlBr3 → CH3+ + AlBr4-

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