1 Nucleophilic substitution

 

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3.3 Halogenoalkanes Page 1 - 3

Oxford Textbook Pages : 206 - 210

CGP Revision Guide Pages : 140 - 141

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Show Specification Ref : 3.3.3.1

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Question 1 / 5

AQA Jan 2010 Paper 2 Q7 areas outside the box will not be scanned for marking a consider the following reaction ch c ch koh ch c ch kbr br oh a i name and outline a mechanism for this reaction name of mechanism mechanism marks a ii name the haloalkane in this reaction mark a iii identify the characteristic of the haloalkane molecule that enables it to undergo this type of reaction mark wmp jan chem areas outside the box will not be scanned for marking b an alternative reaction can occur between this haloalkane and potassium hydroxide as shown by the following equation ch c ch koh ch c ch kbr h o br name and outline a mechanism for this reaction name of mechanism mechanism marks c give one condition needed to favour the reaction shown in part b rather than that shown in part a mark d alkenes can be polymerised to produce poly alkenes d i state the type of polymerisation that alkenes undergo mark d ii name the alkene that gives a polymer with the repeating unit shown below ch c ch name of alkene mark turn over wmp jan chem
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Question 2 / 5

AQA Jan 2011 Paper 2 Q8 do not write outside the box a student read the following passage on the internet haloalkanes contain a polar covalent bond the carbon atom of the polar covalent bond can be attacked by nucleophiles nucleophilic attack enables haloalkanes to undergo substitution reactions a nucleophilic substitution reaction occurs when a haloalkane undergoes hydrolysis the rate of hydrolysis of the haloalkane is influenced by the carbon halogen bond enthalpy a explain the meaning of each of the following terms in the information given above a i nucleophile mark a ii substitution as applied to nucleophilic substitution in a haloalkane mark a iii hydrolysis mark a iv bond enthalpy as applied to a carbon halogen bond mark question continues on the next page turn over wmp jan chem do not write outside the box b outline a mechanism for the nucleophilic substitution reaction in which bromopropane ch chbrch reacts with potassium hydroxide to form propan ol c haloalkanes also undergo elimination reactions to produce alkenes c i outline a mechanism for the elimination reaction in which bromopropane reacts with potassium hydroxide to form propene marks marks wmp jan chem c ii a student obtained the following infrared spectrum for the product from this do not write outside the box elimination reaction transmittance wavenumber cm use information from the infrared spectrum to state and explain how the student deduced that the product was an alkene you may find it helpful to refer to table on the data sheet marks extra space turn over for the next question turn over wmp jan chem
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Question 3 / 5

AQA Jun 2010 Paper 2 Q2 do not write outside the box a a student carried out an experiment to study the rates of hydrolysis of some haloalkanes in the experiment two different haloalkanes were placed in separate test tubes containing silver nitrate solution the haloalkanes reacted with the water in the silver nitrate solution the student timed how long it took for the first appearance of the silver halide precipitate in each tube at a constant temperature this time was used to provide a measure of the initial rate of reaction the student obtained the following results time to form a precipitate s bromobutane iodobutane a i state the meaning of the term hydrolysis mark a ii state the colour of the precipitate formed when iodide ions react with silver nitrate and write the simplest ionic equation for this reaction colour of precipitate simplest ionic equation marks a iii use your knowledge of the reactions of halide ions with silver nitrate to suggest why the student did not include fluorobutane in this experiment marks wmp jun chem do not write outside the box b the student used the following enthalpy data to try to account for the different initial rates of hydrolysis of the haloalkanes used in part a the student deduced that the rate of hydrolysis of a haloalkane is influenced by the strength of the carbon halogen bond in the haloalkane bond enthalpy kj mol c br c i state how the experimental evidence enabled the student to make this deduction mark c the student had read that the reaction of water with haloalkanes was similar to the reaction of aqueous sodium hydroxide with haloalkanes and was an example of a nucleophilic substitution reaction c i state the meaning of the term nucleophile mark c ii when a hydroxide ion collides with a molecule of bromobutane the following reaction occurs ch ch ch ch br oh ch ch ch ch oh br outline the nucleophilic substitution mechanism for this reaction question continues on the next page marks turn over wmp jun chem do not write outside the box d the reaction of hydroxide ions with bromo methylpropane may occur by a different mechanism from the one in part c this different mechanism involves the formation of a carbocation d i complete the following equation by drawing the structure of the carbocation formed when the c br bond in bromo methylpropane is broken ch ch c br ch br mark d ii suggest one reason why this reaction occurs by a mechanism involving a carbocation but the reaction in part c ii does not mark wmp jun chem
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Question 4 / 5

AQA Jun 2013 Paper 4 Q8 section b do not write outside the box answer all questions in the spaces provided a this question is about the primary amine ch ch ch nh the amine ch ch ch nh reacts with ch cocl name and outline a mechanism for this reaction give the iupac name of the organic product marks wmp jun chem do not write outside the box b isomers of ch ch ch nh include another primary amine a secondary amine and a tertiary amine b i draw the structures of these three isomers label each structure as primary secondary or tertiary b ii use table on the data sheet to explain how you could use infrared spectra in the range outside the fingerprint region to distinguish between the secondary amine and the tertiary amine marks marks question continues on the next page turn over wmp jun chem do not write outside the box c the amine ch ch ch nh can be prepared by two different routes route a is a two stage process and starts from ch ch br route b is a one stage process and starts from ch ch ch br c i identify the intermediate compound in route a give the reagents and conditions for both stages in route a and the single stage in route b marks c ii give one disadvantage of route a and one disadvantage of route b marks wmp jun chem
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Question 5 / 5

AQA Jun 2016 Paper 4 Q3 do not write outside the box lidocaine is a local anaesthetic used in dentistry and in minor surgical operations the synthesis of lidocaine in steps from dimethylphenylamine is shown ch nh ch step cl ch c cl ch nh ch ch cl ch nh ch step ch cl h n ch ch ch ch ch a nh ch ch lidocaine b n ch ch ch ch a i give the iupac name of reagent x in step mark a ii outline a mechanism for step in your answer use rnh to represent dimethylphenylamine marks b name the mechanism for step mark wmp jun chem do not write outside the box c which of these is the total number of peaks in the c n m r spectrum of lidocaine tick one box d calculate the percentage by mass of hydrogen in a molecule of lidocaine mark marks e give the name including the classification of the functional group that contains the nitrogen atom labelled b mark f lidocaine is used medically as the salt lidocaine hydrochloride f i suggest which one of the nitrogen atoms labelled a or b is protonated in lidocaine hydrochloride explain your answer marks nitrogen atom protonated explanation f ii suggest why lidocaine hydrochloride is used medically in preference to lidocaine explain your answer marks turn over wmp jun chem
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