Lesson 3.3.11.3

3.3.11.3 Nucleophilic properties Quiz: AQA Chemistry, Unit 3

20 questions

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Lesson 3.3.11.3, Nucleophilic properties: 20 multiple choice questions for the AQA Chemistry (7405), Unit 3: Organic chemistry, written with Revision Ninja.

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The 20 questions

  1. Why are amines nucleophiles?

    • Their nitrogen lone pair is donated to an electron-deficient carbon atom
    • They always lose a proton to form an acid, which makes them react with carbon
    • They contain a carbon-carbon double bond that adds to electron-rich centres
    • They carry a full positive charge on nitrogen, so they attract nucleophiles
  2. What is the main first product when excess ammonia reacts with a halogenoalkane?

    • A quaternary ammonium salt
    • A tertiary amine
    • An amide
    • A primary amine
  3. Which species is a quaternary ammonium salt?

    • A nitrogen atom with one alkyl group and a lone pair, which can form a salt
    • A nitrogen atom bonded to four alkyl groups with a positive charge
    • A nitrogen atom in a benzene ring, which is an aromatic quaternary centre in the ring
    • A carbon atom bonded to four hydrogen atoms, which is the usual nucleophile in substitution
  4. What are quaternary ammonium salts used for in the specification?

    • Dye intermediates
    • Polyalkene manufacture
    • Biodiesel fuel
    • Cationic surfactants
  5. What product forms when a primary amine such as methylamine reacts with ethanoyl chloride?

    • Methyl ethanoate
    • Ethanamide
    • Ethanoic acid
    • N-methylethanamide
  6. What is the first step when ammonia attacks bromoethane?

    • The lone pair on nitrogen attacks the carbon bonded to bromine
    • Bromine atom attacks the nitrogen atom, pulling the lone pair towards the halogen
    • A proton is removed from the nitrogen, forming an imine that then reacts with bromine
    • The C-C bond breaks to form ethene, which then adds ammonia across the double bond
  7. What is the product when ethylamine reacts with bromoethane?

    • Diethylamine
    • Tetraethylammonium bromide
    • Triethylamine
    • Ethanamine
  8. What is the product when triethylamine reacts with excess bromoethane?

    • Tetraethylammonium bromide, which forms directly from one bromoethane and ammonia
    • Ethylamine, which is simply left over unchanged because it is a poor nucleophile
    • Tetraethylammonium bromide
    • Ethanamide, which forms when bromoethane is oxidised by the excess ammonia present
  9. Why is ethylamine a better nucleophile than phenylamine toward bromoethane?

    • Ethylamine contains a triple bond that makes it react with bromoethane by an addition mechanism
    • Its lone pair is more available because the ethyl group is electron-donating and the lone pair is not delocalised into a ring
    • Bromoethane reacts only with phenylamine and never with the alkylamine present in the mixture
    • Phenylamine contains no lone pair on nitrogen, so it cannot act as a nucleophile at all here
  10. Why is excess ammonia used to make a primary amine from a halogenoalkane?

    • It converts the halogenoalkane into an alkene by elimination before any amine has time to form
    • It removes the bromide ion from the solution by precipitating it as insoluble silver bromide
    • It makes the halogenoalkane more likely to meet a stronger nucleophile than the amine, so substitution is increased
    • It makes collision with the halogenoalkane more likely than with the product amine, reducing further substitution
  11. Which species is the nucleophile in the reaction of ammonia with bromoethane?

    • The hydrogen atoms of ammonia, which are removed by the halogenoalkane to form a salt
    • The bromine atom of bromoethane, which is the nucleophile that attacks the amine
    • The lone pair on the nitrogen atom of NH3
    • The carbon atom of bromoethane, which carries a lone pair that it donates to ammonia
  12. What is the leaving species in the addition-elimination reaction of ammonia with ethanoyl chloride?

    • Chloride ion, Cl-
    • Hydride ion, H-
    • Ammonium ion, NH4+
    • Hydroxide ion, OH-
  13. Why is ethanoyl chloride used rather than ethanoic acid to make an amide?

    • The acyl chloride carbonyl carbon is more electrophilic and reacts readily under mild conditions
    • Ethanoic acid cannot form any bond to nitrogen, so it cannot react with the amine
    • Ethanoyl chloride contains a nitrogen atom that makes it react with amines readily
    • Ethanoic acid is a gas at room temperature, so it cannot be mixed with the amine
  14. What happens to the HCl formed when a primary amine reacts with an acyl chloride?

    • It is converted into methane
    • It is removed by reaction with excess amine to form a salt
    • It remains dissolved and acts as the nucleophile
    • It is released as a gas and changes the amide to an ester
  15. Why are quaternary ammonium salts effective cationic surfactants?

    • They are anions that repel all surfaces and so prevent any cleaning action in a detergent solution
    • Their negative head is attracted to positive surfaces while their hydrophobic alkyl tails repel grease
    • Their positive head is attracted to negative surfaces while their hydrophobic alkyl tails can interact with grease
    • They are neutral molecules that dissolve in oil only and do not affect the surfaces they touch
  16. Which statement about quaternary ammonium compounds is correct?

    • The nitrogen carries a permanent positive charge because it has four bonds to alkyl groups
    • The nitrogen carries a negative charge when four alkyl groups are present
    • They are always gases at room temperature
    • The nitrogen has a lone pair that makes the salt a base
  17. Which species is the electrophile in the addition-elimination reaction of an amine with an acyl chloride?

    • The carbonyl carbon of the acyl chloride
    • The hydrogen atom of the amine
    • The nitrogen lone pair of the amine
    • The chlorine atom of the acyl chloride
  18. What is the mass of ethylamine (C2H7N, Mr 45) formed from 0.1 mol of bromoethane with excess ammonia?

    • 4.5 g
    • 45 g
    • 2.25 g
    • 9.0 g
  19. What happens when a primary amine reacts with an acid anhydride?

    • It forms an ester and hydrogen chloride, as a condensation product of the amine
    • It forms an N-substituted amide and a carboxylic acid by-product
    • It forms a nitrile and water, because the amine is dehydrated by the anhydride
    • It forms a quaternary salt only, because the amine is always fully alkylated
  20. Which statement about the product of a primary amine with an acyl chloride is correct?

    • It is an alkene
    • It is a carboxylic acid with no nitrogen
    • It is an N-substituted amide
    • It is a quaternary ammonium salt

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